remove either crate conversions

split up router pattern and resource_path modules
align remaining header map terminology (#2510 )
2025-08-30 16:40:21 +02:00 · 2021-12-14 19:01:14 +00:00 · 2021-12-14 18:59:59 +00:00 · 2021-12-13 16:08:08 +00:00 · 2021-12-13 02:58:19 +00:00 · 2021-12-11 16:18:28 +00:00
105 changed files with 1525 additions and 1228 deletions
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -2,6 +2,22 @@

 ## Unreleased - 2021-xx-xx
 ### Added
+* Method on `Responder` trait (`customize`) for customizing responders and `CustomizeResponder` struct. [#2510]
+* Implement `Debug` for `DefaultHeaders`. [#2510]
+
+### Changed
+* Align `DefaultHeader` method terminology, deprecating previous methods. [#2510]
+
+### Removed
+* Top-level `EitherExtractError` export. [#2510]
+* Conversion implementations for `either` crate. [#2516]
+
+[#2510]: https://github.com/actix/actix-web/pull/2510
+[#2516]: https://github.com/actix/actix-web/pull/2516
+
+
+## 4.0.0-beta.14 - 2021-12-11
+### Added
 * Methods on `AcceptLanguage`: `ranked` and `preference`. [#2480]
 * `AcceptEncoding` typed header. [#2482]
 * `Range` typed header. [#2485]
@@ -9,6 +25,7 @@
 * `ServiceResponse::map_into_{left,right}_body` and `HttpResponse::map_into_boxed_body`. [#2468]
 * Connection data set through the `HttpServer::on_connect` callback is now accessible only from the new `HttpRequest::conn_data()` and `ServiceRequest::conn_data()` methods. [#2491]
 * `HttpRequest::{req_data,req_data_mut}`. [#2487]
+* `ServiceResponse::into_parts`. [#2499]

 ### Changed
 * Rename `Accept::{mime_precedence => ranked}`. [#2480]
@@ -37,6 +54,7 @@
 [#2491]: https://github.com/actix/actix-web/pull/2491
 [#2492]: https://github.com/actix/actix-web/pull/2492
 [#2493]: https://github.com/actix/actix-web/pull/2493
+[#2499]: https://github.com/actix/actix-web/pull/2499


 ## 4.0.0-beta.13 - 2021-11-30
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "actix-web"
-version = "4.0.0-beta.13"
+version = "4.0.0-beta.14"
 authors = ["Nikolay Kim <fafhrd91@gmail.com>"]
 description = "Actix Web is a powerful, pragmatic, and extremely fast web framework for Rust"
 keywords = ["actix", "http", "web", "framework", "async"]
@@ -77,16 +77,15 @@ actix-service = "2.0.0"
 actix-utils = "3.0.0"
 actix-tls = { version = "3.0.0-rc.1", default-features = false, optional = true }

-actix-http = "3.0.0-beta.14"
+actix-http = "3.0.0-beta.15"
 actix-router = "0.5.0-beta.2"
-actix-web-codegen = "0.5.0-beta.5"
+actix-web-codegen = "0.5.0-beta.6"

 ahash = "0.7"
 bytes = "1"
 cfg-if = "1"
 cookie = { version = "0.15", features = ["percent-encode"], optional = true }
 derive_more = "0.99.5"
-either = "1.5.3"
 encoding_rs = "0.8"
 futures-core = { version = "0.3.7", default-features = false }
 futures-util = { version = "0.3.7", default-features = false }
@@ -107,8 +106,8 @@ time = { version = "0.3", default-features = false, features = ["formatting"] }
 url = "2.1"

 [dev-dependencies]
-actix-test = { version = "0.1.0-beta.7", features = ["openssl", "rustls"] }
-awc = { version = "3.0.0-beta.11", features = ["openssl"] }
+actix-test = { version = "0.1.0-beta.8", features = ["openssl", "rustls"] }
+awc = { version = "3.0.0-beta.13", features = ["openssl"] }

 brotli2 = "0.3.2"
 criterion = { version = "0.3", features = ["html_reports"] }
@@ -118,7 +117,6 @@ futures-util = { version = "0.3.7", default-features = false, features = ["std"]
 rand = "0.8"
 rcgen = "0.8"
 rustls-pemfile = "0.2"
-static_assertions = "1"
 tls-openssl = { package = "openssl", version = "0.10.9" }
 tls-rustls = { package = "rustls", version = "0.20.0" }
 zstd = "0.9"
--- a/README.md
+++ b/README.md
@@ -6,10 +6,10 @@
  <p>

 [![crates.io](https://img.shields.io/crates/v/actix-web?label=latest)](https://crates.io/crates/actix-web)
-[![Documentation](https://docs.rs/actix-web/badge.svg?version=4.0.0-beta.13)](https://docs.rs/actix-web/4.0.0-beta.13)
+[![Documentation](https://docs.rs/actix-web/badge.svg?version=4.0.0-beta.14)](https://docs.rs/actix-web/4.0.0-beta.14)
 [![Version](https://img.shields.io/badge/rustc-1.52+-ab6000.svg)](https://blog.rust-lang.org/2021/05/06/Rust-1.52.0.html)
 ![MIT or Apache 2.0 licensed](https://img.shields.io/crates/l/actix-web.svg)
-[![Dependency Status](https://deps.rs/crate/actix-web/4.0.0-beta.13/status.svg)](https://deps.rs/crate/actix-web/4.0.0-beta.13)
+[![Dependency Status](https://deps.rs/crate/actix-web/4.0.0-beta.14/status.svg)](https://deps.rs/crate/actix-web/4.0.0-beta.14)
 <br />
 [![build status](https://github.com/actix/actix-web/workflows/CI%20%28Linux%29/badge.svg?branch=master&event=push)](https://github.com/actix/actix-web/actions)
 [![codecov](https://codecov.io/gh/actix/actix-web/branch/master/graph/badge.svg)](https://codecov.io/gh/actix/actix-web) 
--- a/actix-files/CHANGES.md
+++ b/actix-files/CHANGES.md
@@ -3,6 +3,10 @@
 ## Unreleased - 2021-xx-xx


+## 0.6.0-beta.10 - 2021-12-11
+* No significant changes since `0.6.0-beta.9`.
+
+
 ## 0.6.0-beta.9 - 2021-11-22
 * Add crate feature `experimental-io-uring`, enabling async file I/O to be utilized. This feature is only available on Linux OSes with recent kernel versions. This feature is semver-exempt. [#2408]
 * Add `NamedFile::open_async`. [#2408]
--- a/actix-files/Cargo.toml
+++ b/actix-files/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "actix-files"
-version = "0.6.0-beta.9"
+version = "0.6.0-beta.10"
 authors = [
    "Nikolay Kim <fafhrd91@gmail.com>",
    "fakeshadow <24548779@qq.com>",
@@ -22,17 +22,17 @@ path = "src/lib.rs"
 experimental-io-uring = ["actix-web/experimental-io-uring", "tokio-uring"]

 [dependencies]
-actix-web = { version = "4.0.0-beta.11", default-features = false }
-actix-http = "3.0.0-beta.14"
+actix-http = "3.0.0-beta.15"
 actix-service = "2"
 actix-utils = "3"
+actix-web = { version = "4.0.0-beta.14", default-features = false }

 askama_escape = "0.10"
 bitflags = "1"
 bytes = "1"
+derive_more = "0.99.5"
 futures-core = { version = "0.3.7", default-features = false, features = ["alloc"] }
 http-range = "0.1.4"
-derive_more = "0.99.5"
 log = "0.4"
 mime = "0.3"
 mime_guess = "2.0.1"
@@ -43,5 +43,5 @@ tokio-uring = { version = "0.1", optional = true }

 [dev-dependencies]
 actix-rt = "2.2"
-actix-web = "4.0.0-beta.11"
-actix-test = "0.1.0-beta.7"
+actix-test = "0.1.0-beta.8"
+actix-web = "4.0.0-beta.14"
--- a/actix-files/README.md
+++ b/actix-files/README.md
@@ -3,11 +3,11 @@
 > Static file serving for Actix Web

 [![crates.io](https://img.shields.io/crates/v/actix-files?label=latest)](https://crates.io/crates/actix-files)
-[![Documentation](https://docs.rs/actix-files/badge.svg?version=0.6.0-beta.9)](https://docs.rs/actix-files/0.6.0-beta.9)
+[![Documentation](https://docs.rs/actix-files/badge.svg?version=0.6.0-beta.10)](https://docs.rs/actix-files/0.6.0-beta.10)
 [![Version](https://img.shields.io/badge/rustc-1.52+-ab6000.svg)](https://blog.rust-lang.org/2021/05/06/Rust-1.52.0.html)
 ![License](https://img.shields.io/crates/l/actix-files.svg)
 <br />
-[![dependency status](https://deps.rs/crate/actix-files/0.6.0-beta.9/status.svg)](https://deps.rs/crate/actix-files/0.6.0-beta.9)
+[![dependency status](https://deps.rs/crate/actix-files/0.6.0-beta.10/status.svg)](https://deps.rs/crate/actix-files/0.6.0-beta.10)
 [![Download](https://img.shields.io/crates/d/actix-files.svg)](https://crates.io/crates/actix-files)
 [![Chat on Discord](https://img.shields.io/discord/771444961383153695?label=chat&logo=discord)](https://discord.gg/NWpN5mmg3x)

--- a/actix-files/src/named.rs
+++ b/actix-files/src/named.rs
@@ -2,14 +2,10 @@ use std::{
    fmt,
    fs::Metadata,
    io,
-    ops::{Deref, DerefMut},
    path::{Path, PathBuf},
    time::{SystemTime, UNIX_EPOCH},
 };

-#[cfg(unix)]
-use std::os::unix::fs::MetadataExt;
-
 use actix_service::{Service, ServiceFactory};
 use actix_web::{
    body::{self, BoxBody, SizedStream},
@@ -27,6 +23,7 @@ use actix_web::{
    Error, HttpMessage, HttpRequest, HttpResponse, Responder,
 };
 use bitflags::bitflags;
+use derive_more::{Deref, DerefMut};
 use futures_core::future::LocalBoxFuture;
 use mime_guess::from_path;

@@ -71,8 +68,11 @@ impl Default for Flags {
 ///     NamedFile::open_async("./static/index.html").await
 /// }
 /// ```
+#[derive(Deref, DerefMut)]
 pub struct NamedFile {
    path: PathBuf,
+    #[deref]
+    #[deref_mut]
    file: File,
    modified: Option<SystemTime>,
    pub(crate) md: Metadata,
@@ -364,14 +364,18 @@ impl NamedFile {
        self
    }

+    /// Creates a etag in a format is similar to Apache's.
    pub(crate) fn etag(&self) -> Option<header::EntityTag> {
-        // This etag format is similar to Apache's.
        self.modified.as_ref().map(|mtime| {
            let ino = {
                #[cfg(unix)]
                {
+                    #[cfg(unix)]
+                    use std::os::unix::fs::MetadataExt as _;
+
                    self.md.ino()
                }
+
                #[cfg(not(unix))]
                {
                    0
@@ -472,17 +476,17 @@ impl NamedFile {
            false
        };

-        let mut resp = HttpResponse::build(self.status_code);
+        let mut res = HttpResponse::build(self.status_code);

        if self.flags.contains(Flags::PREFER_UTF8) {
            let ct = equiv_utf8_text(self.content_type.clone());
-            resp.insert_header((header::CONTENT_TYPE, ct.to_string()));
+            res.insert_header((header::CONTENT_TYPE, ct.to_string()));
        } else {
-            resp.insert_header((header::CONTENT_TYPE, self.content_type.to_string()));
+            res.insert_header((header::CONTENT_TYPE, self.content_type.to_string()));
        }

        if self.flags.contains(Flags::CONTENT_DISPOSITION) {
-            resp.insert_header((
+            res.insert_header((
                header::CONTENT_DISPOSITION,
                self.content_disposition.to_string(),
            ));
@@ -490,18 +494,18 @@ impl NamedFile {

        // default compressing
        if let Some(current_encoding) = self.encoding {
-            resp.encoding(current_encoding);
+            res.encoding(current_encoding);
        }

        if let Some(lm) = last_modified {
-            resp.insert_header((header::LAST_MODIFIED, lm.to_string()));
+            res.insert_header((header::LAST_MODIFIED, lm.to_string()));
        }

        if let Some(etag) = etag {
-            resp.insert_header((header::ETAG, etag.to_string()));
+            res.insert_header((header::ETAG, etag.to_string()));
        }

-        resp.insert_header((header::ACCEPT_RANGES, "bytes"));
+        res.insert_header((header::ACCEPT_RANGES, "bytes"));

        let mut length = self.md.len();
        let mut offset = 0;
@@ -513,24 +517,24 @@ impl NamedFile {
                    length = ranges[0].length;
                    offset = ranges[0].start;

-                    resp.encoding(ContentEncoding::Identity);
-                    resp.insert_header((
+                    res.encoding(ContentEncoding::Identity);
+                    res.insert_header((
                        header::CONTENT_RANGE,
                        format!("bytes {}-{}/{}", offset, offset + length - 1, self.md.len()),
                    ));
                } else {
-                    resp.insert_header((header::CONTENT_RANGE, format!("bytes */{}", length)));
-                    return resp.status(StatusCode::RANGE_NOT_SATISFIABLE).finish();
+                    res.insert_header((header::CONTENT_RANGE, format!("bytes */{}", length)));
+                    return res.status(StatusCode::RANGE_NOT_SATISFIABLE).finish();
                };
            } else {
-                return resp.status(StatusCode::BAD_REQUEST).finish();
+                return res.status(StatusCode::BAD_REQUEST).finish();
            };
        };

        if precondition_failed {
-            return resp.status(StatusCode::PRECONDITION_FAILED).finish();
+            return res.status(StatusCode::PRECONDITION_FAILED).finish();
        } else if not_modified {
-            return resp
+            return res
                .status(StatusCode::NOT_MODIFIED)
                .body(body::None::new())
                .map_into_boxed_body();
@@ -539,10 +543,10 @@ impl NamedFile {
        let reader = chunked::new_chunked_read(length, offset, self.file);

        if offset != 0 || length != self.md.len() {
-            resp.status(StatusCode::PARTIAL_CONTENT);
+            res.status(StatusCode::PARTIAL_CONTENT);
        }

-        resp.body(SizedStream::new(length, reader))
+        res.body(SizedStream::new(length, reader))
    }
 }

@@ -586,20 +590,6 @@ fn none_match(etag: Option<&header::EntityTag>, req: &HttpRequest) -> bool {
    }
 }

-impl Deref for NamedFile {
-    type Target = File;
-
-    fn deref(&self) -> &Self::Target {
-        &self.file
-    }
-}
-
-impl DerefMut for NamedFile {
-    fn deref_mut(&mut self) -> &mut Self::Target {
-        &mut self.file
-    }
-}
-
 impl Responder for NamedFile {
    type Body = BoxBody;

--- a/actix-http-test/CHANGES.md
+++ b/actix-http-test/CHANGES.md
@@ -3,6 +3,10 @@
 ## Unreleased - 2021-xx-xx


+## 3.0.0-beta.9 - 2021-12-11
+* No significant changes since `3.0.0-beta.8`.
+
+
 ## 3.0.0-beta.8 - 2021-11-30
 * Update `actix-tls` to `3.0.0-rc.1`. [#2474]

--- a/actix-http-test/Cargo.toml
+++ b/actix-http-test/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "actix-http-test"
-version = "3.0.0-beta.8"
+version = "3.0.0-beta.9"
 authors = ["Nikolay Kim <fafhrd91@gmail.com>"]
 description = "Various helpers for Actix applications to use during testing"
 keywords = ["http", "web", "framework", "async", "futures"]
@@ -35,7 +35,7 @@ actix-tls = "3.0.0-rc.1"
 actix-utils = "3.0.0"
 actix-rt = "2.2"
 actix-server = "2.0.0-rc.1"
-awc = { version = "3.0.0-beta.11", default-features = false }
+awc = { version = "3.0.0-beta.13", default-features = false }

 base64 = "0.13"
 bytes = "1"
@@ -51,5 +51,5 @@ tls-openssl = { version = "0.10.9", package = "openssl", optional = true }
 tokio = { version = "1.2", features = ["sync"] }

 [dev-dependencies]
-actix-web = { version = "4.0.0-beta.11", default-features = false, features = ["cookies"] }
-actix-http = "3.0.0-beta.14"
+actix-web = { version = "4.0.0-beta.14", default-features = false, features = ["cookies"] }
+actix-http = "3.0.0-beta.15"
--- a/actix-http-test/README.md
+++ b/actix-http-test/README.md
@@ -3,11 +3,11 @@
 > Various helpers for Actix applications to use during testing.

 [![crates.io](https://img.shields.io/crates/v/actix-http-test?label=latest)](https://crates.io/crates/actix-http-test)
-[![Documentation](https://docs.rs/actix-http-test/badge.svg?version=3.0.0-beta.8)](https://docs.rs/actix-http-test/3.0.0-beta.8)
+[![Documentation](https://docs.rs/actix-http-test/badge.svg?version=3.0.0-beta.9)](https://docs.rs/actix-http-test/3.0.0-beta.9)
 [![Version](https://img.shields.io/badge/rustc-1.52+-ab6000.svg)](https://blog.rust-lang.org/2021/05/06/Rust-1.52.0.html)
 ![MIT or Apache 2.0 licensed](https://img.shields.io/crates/l/actix-http-test)
 <br>
-[![Dependency Status](https://deps.rs/crate/actix-http-test/3.0.0-beta.8/status.svg)](https://deps.rs/crate/actix-http-test/3.0.0-beta.8)
+[![Dependency Status](https://deps.rs/crate/actix-http-test/3.0.0-beta.9/status.svg)](https://deps.rs/crate/actix-http-test/3.0.0-beta.9)
 [![Download](https://img.shields.io/crates/d/actix-http-test.svg)](https://crates.io/crates/actix-http-test)
 [![Chat on Discord](https://img.shields.io/discord/771444961383153695?label=chat&logo=discord)](https://discord.gg/NWpN5mmg3x)

--- a/actix-http/CHANGES.md
+++ b/actix-http/CHANGES.md
@@ -1,6 +1,15 @@
 # Changes

 ## Unreleased - 2021-xx-xx
+### Changed
+* Rename trait `IntoHeaderPair => TryIntoHeaderPair`. [#2510]
+* Rename `TryIntoHeaderPair::{try_into_header_pair => try_into_pair}`. [#2510]
+* Rename trait `IntoHeaderValue => TryIntoHeaderValue`. [#2510]
+
+[#2510]: https://github.com/actix/actix-web/pull/2510
+
+
+## 3.0.0-beta.15 - 2021-12-11
 ### Added
 * Add timeout for canceling HTTP/2 server side connection handshake. Default to 5 seconds. [#2483]
 * HTTP/2 handshake timeout can be configured with `ServiceConfig::client_timeout`. [#2483]
@@ -18,6 +27,7 @@
 * `Request::take_conn_data()`. [#2491]
 * `Request::take_req_data()`. [#2487]
 * `impl Clone` for `RequestHead`. [#2487]
+* New methods on `MessageBody` trait, `is_complete_body` and `take_complete_body`, both with default implementations, for optimisations on body types that are done in exactly one poll/chunk. [#2497]

 ### Changed
 * Rename `body::BoxBody::{from_body => new}`. [#2468]
@@ -45,6 +55,7 @@
 [#2487]: https://github.com/actix/actix-web/pull/2487
 [#2488]: https://github.com/actix/actix-web/pull/2488
 [#2491]: https://github.com/actix/actix-web/pull/2491
+[#2497]: https://github.com/actix/actix-web/pull/2497


 ## 3.0.0-beta.14 - 2021-11-30
@@ -255,7 +266,7 @@

 ## 3.0.0-beta.2 - 2021-02-10
 ### Added
-* `IntoHeaderPair` trait that allows using typed and untyped headers in the same methods. [#1869]
+* `TryIntoHeaderPair` trait that allows using typed and untyped headers in the same methods. [#1869]
 * `ResponseBuilder::insert_header` method which allows using typed headers. [#1869]
 * `ResponseBuilder::append_header` method which allows using typed headers. [#1869]
 * `TestRequest::insert_header` method which allows using typed headers. [#1869]
@@ -266,9 +277,9 @@
 * `trust-dns` optional feature to enable `trust-dns-resolver` as client dns resolver. [#1969]

 ### Changed
-* `ResponseBuilder::content_type` now takes an `impl IntoHeaderValue` to support using typed
+* `ResponseBuilder::content_type` now takes an `impl TryIntoHeaderValue` to support using typed
  `mime` types. [#1894]
-* Renamed `IntoHeaderValue::{try_into => try_into_value}` to avoid ambiguity with std
+* Renamed `TryIntoHeaderValue::{try_into => try_into_value}` to avoid ambiguity with std
  `TryInto` trait. [#1894]
 * `Extensions::insert` returns Option of replaced item. [#1904]
 * Remove `HttpResponseBuilder::json2()`. [#1903]
--- a/actix-http/Cargo.toml
+++ b/actix-http/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "actix-http"
-version = "3.0.0-beta.14"
+version = "3.0.0-beta.15"
 authors = ["Nikolay Kim <fafhrd91@gmail.com>"]
 description = "HTTP primitives for the Actix ecosystem"
 keywords = ["actix", "http", "framework", "async", "futures"]
@@ -56,7 +56,7 @@ derive_more = "0.99.5"
 encoding_rs = "0.8"
 futures-core = { version = "0.3.7", default-features = false, features = ["alloc"] }
 futures-util = { version = "0.3.7", default-features = false, features = ["alloc", "sink"] }
-h2 = "0.3.1"
+h2 = "0.3.9"
 http = "0.2.5"
 httparse = "1.5.1"
 httpdate = "1.0.1"
@@ -81,10 +81,11 @@ flate2 = { version = "1.0.13", optional = true }
 zstd = { version = "0.9", optional = true }

 [dev-dependencies]
+actix-http-test = { version = "3.0.0-beta.9", features = ["openssl"] }
 actix-server = "2.0.0-rc.1"
-actix-http-test = { version = "3.0.0-beta.7", features = ["openssl"] }
 actix-tls = { version = "3.0.0-rc.1", features = ["openssl"] }
-actix-web = "4.0.0-beta.13"
+actix-web = "4.0.0-beta.14"
+
 async-stream = "0.3"
 criterion = { version = "0.3", features = ["html_reports"] }
 env_logger = "0.9"
--- a/actix-http/README.md
+++ b/actix-http/README.md
@@ -3,11 +3,11 @@
 > HTTP primitives for the Actix ecosystem.

 [![crates.io](https://img.shields.io/crates/v/actix-http?label=latest)](https://crates.io/crates/actix-http)
-[![Documentation](https://docs.rs/actix-http/badge.svg?version=3.0.0-beta.14)](https://docs.rs/actix-http/3.0.0-beta.14)
+[![Documentation](https://docs.rs/actix-http/badge.svg?version=3.0.0-beta.15)](https://docs.rs/actix-http/3.0.0-beta.15)
 [![Version](https://img.shields.io/badge/rustc-1.52+-ab6000.svg)](https://blog.rust-lang.org/2021/05/06/Rust-1.52.0.html)
 ![MIT or Apache 2.0 licensed](https://img.shields.io/crates/l/actix-http.svg)
 <br />
-[![dependency status](https://deps.rs/crate/actix-http/3.0.0-beta.14/status.svg)](https://deps.rs/crate/actix-http/3.0.0-beta.14)
+[![dependency status](https://deps.rs/crate/actix-http/3.0.0-beta.15/status.svg)](https://deps.rs/crate/actix-http/3.0.0-beta.15)
 [![Download](https://img.shields.io/crates/d/actix-http.svg)](https://crates.io/crates/actix-http)
 [![Chat on Discord](https://img.shields.io/discord/771444961383153695?label=chat&logo=discord)](https://discord.gg/NWpN5mmg3x)

--- a/actix-http/src/body/body_stream.rs
+++ b/actix-http/src/body/body_stream.rs
@@ -27,6 +27,7 @@ where
    S: Stream<Item = Result<Bytes, E>>,
    E: Into<Box<dyn StdError>> + 'static,
 {
+    #[inline]
    pub fn new(stream: S) -> Self {
        BodyStream { stream }
    }
@@ -39,6 +40,7 @@ where
 {
    type Error = E;

+    #[inline]
    fn size(&self) -> BodySize {
        BodySize::Stream
    }
--- a/actix-http/src/body/boxed.rs
+++ b/actix-http/src/body/boxed.rs
@@ -51,6 +51,34 @@ impl MessageBody for BoxBody {
            .poll_next(cx)
            .map_err(|err| Error::new_body().with_cause(err))
    }
+
+    fn is_complete_body(&self) -> bool {
+        self.0.is_complete_body()
+    }
+
+    fn take_complete_body(&mut self) -> Bytes {
+        debug_assert!(
+            self.is_complete_body(),
+            "boxed type does not allow taking complete body; caller should make sure to \
+            call `is_complete_body` first",
+        );
+
+        // we do not have DerefMut access to call take_complete_body directly but since
+        // is_complete_body is true we should expect the entire bytes chunk in one poll_next
+
+        let waker = futures_util::task::noop_waker();
+        let mut cx = Context::from_waker(&waker);
+
+        match self.as_pin_mut().poll_next(&mut cx) {
+            Poll::Ready(Some(Ok(data))) => data,
+            _ => {
+                panic!(
+                    "boxed type indicated it allows taking complete body but failed to \
+                    return Bytes when polled",
+                );
+            }
+        }
+    }
 }

 #[cfg(test)]
--- a/actix-http/src/body/either.rs
+++ b/actix-http/src/body/either.rs
@@ -23,6 +23,7 @@ pin_project! {

 impl<L> EitherBody<L, BoxBody> {
    /// Creates new `EitherBody` using left variant and boxed right variant.
+    #[inline]
    pub fn new(body: L) -> Self {
        Self::Left { body }
    }
@@ -30,11 +31,13 @@ impl<L> EitherBody<L, BoxBody> {

 impl<L, R> EitherBody<L, R> {
    /// Creates new `EitherBody` using left variant.
+    #[inline]
    pub fn left(body: L) -> Self {
        Self::Left { body }
    }

    /// Creates new `EitherBody` using right variant.
+    #[inline]
    pub fn right(body: R) -> Self {
        Self::Right { body }
    }
@@ -47,6 +50,7 @@ where
 {
    type Error = Error;

+    #[inline]
    fn size(&self) -> BodySize {
        match self {
            EitherBody::Left { body } => body.size(),
@@ -54,6 +58,7 @@ where
        }
    }

+    #[inline]
    fn poll_next(
        self: Pin<&mut Self>,
        cx: &mut Context<'_>,
@@ -67,6 +72,22 @@ where
                .map_err(|err| Error::new_body().with_cause(err)),
        }
    }
+
+    #[inline]
+    fn is_complete_body(&self) -> bool {
+        match self {
+            EitherBody::Left { body } => body.is_complete_body(),
+            EitherBody::Right { body } => body.is_complete_body(),
+        }
+    }
+
+    #[inline]
+    fn take_complete_body(&mut self) -> Bytes {
+        match self {
+            EitherBody::Left { body } => body.take_complete_body(),
+            EitherBody::Right { body } => body.take_complete_body(),
+        }
+    }
 }

 #[cfg(test)]
--- a/actix-http/src/body/message_body.rs
+++ b/actix-http/src/body/message_body.rs
@@ -19,16 +19,64 @@ use super::BodySize;
 pub trait MessageBody {
    // TODO: consider this bound to only fmt::Display since the error type is not really used
    // and there is an impl for Into<Box<StdError>> on String
-    type Error: Into<Box<dyn StdError>> + 'static;
+    type Error: Into<Box<dyn StdError>>;

    /// Body size hint.
    fn size(&self) -> BodySize;

    /// Attempt to pull out the next chunk of body bytes.
+    // TODO: expand documentation
    fn poll_next(
        self: Pin<&mut Self>,
        cx: &mut Context<'_>,
    ) -> Poll<Option<Result<Bytes, Self::Error>>>;
+
+    /// Returns true if entire body bytes chunk is obtainable in one call to `poll_next`.
+    ///
+    /// This method's implementation should agree with [`take_complete_body`] and should always be
+    /// checked before taking the body.
+    ///
+    /// The default implementation returns `false.
+    ///
+    /// [`take_complete_body`]: MessageBody::take_complete_body
+    fn is_complete_body(&self) -> bool {
+        false
+    }
+
+    /// Returns the complete chunk of body bytes.
+    ///
+    /// Implementors of this method should note the following:
+    /// - It is acceptable to skip the omit checks of [`is_complete_body`]. The responsibility of
+    ///   performing this check is delegated to the caller.
+    /// - If the result of [`is_complete_body`] is conditional, that condition should be given
+    ///   equivalent attention here.
+    /// - A second call call to [`take_complete_body`] should return an empty `Bytes` or panic.
+    /// - A call to [`poll_next`] after calling [`take_complete_body`] should return `None` unless
+    ///   the chunk is guaranteed to be empty.
+    ///
+    /// The default implementation panics unconditionally, indicating a control flow bug in the
+    /// calling code.
+    ///
+    /// # Panics
+    /// With a correct implementation, panics if called without first checking [`is_complete_body`].
+    ///
+    /// [`is_complete_body`]: MessageBody::is_complete_body
+    /// [`take_complete_body`]: MessageBody::take_complete_body
+    /// [`poll_next`]: MessageBody::poll_next
+    fn take_complete_body(&mut self) -> Bytes {
+        assert!(
+            self.is_complete_body(),
+            "type ({}) allows taking complete body but did not provide an implementation \
+            of `take_complete_body`",
+            std::any::type_name::<Self>()
+        );
+
+        unimplemented!(
+            "type ({}) does not allow taking complete body; caller should make sure to \
+            check `is_complete_body` first",
+            std::any::type_name::<Self>()
+        );
+    }
 }

 mod foreign_impls {
@@ -37,18 +85,24 @@ mod foreign_impls {
    impl MessageBody for Infallible {
        type Error = Infallible;

-        #[inline]
        fn size(&self) -> BodySize {
            match *self {}
        }

-        #[inline]
        fn poll_next(
            self: Pin<&mut Self>,
            _cx: &mut Context<'_>,
        ) -> Poll<Option<Result<Bytes, Self::Error>>> {
            match *self {}
        }
+
+        fn is_complete_body(&self) -> bool {
+            true
+        }
+
+        fn take_complete_body(&mut self) -> Bytes {
+            match *self {}
+        }
    }

    impl MessageBody for () {
@@ -66,6 +120,16 @@ mod foreign_impls {
        ) -> Poll<Option<Result<Bytes, Self::Error>>> {
            Poll::Ready(None)
        }
+
+        #[inline]
+        fn is_complete_body(&self) -> bool {
+            true
+        }
+
+        #[inline]
+        fn take_complete_body(&mut self) -> Bytes {
+            Bytes::new()
+        }
    }

    impl<B> MessageBody for Box<B>
@@ -86,6 +150,16 @@ mod foreign_impls {
        ) -> Poll<Option<Result<Bytes, Self::Error>>> {
            Pin::new(self.get_mut().as_mut()).poll_next(cx)
        }
+
+        #[inline]
+        fn is_complete_body(&self) -> bool {
+            self.as_ref().is_complete_body()
+        }
+
+        #[inline]
+        fn take_complete_body(&mut self) -> Bytes {
+            self.as_mut().take_complete_body()
+        }
    }

    impl<B> MessageBody for Pin<Box<B>>
@@ -106,92 +180,164 @@ mod foreign_impls {
        ) -> Poll<Option<Result<Bytes, Self::Error>>> {
            self.as_mut().poll_next(cx)
        }
+
+        #[inline]
+        fn is_complete_body(&self) -> bool {
+            self.as_ref().is_complete_body()
+        }
+
+        #[inline]
+        fn take_complete_body(&mut self) -> Bytes {
+            debug_assert!(
+                self.is_complete_body(),
+                "inner type \"{}\" does not allow taking complete body; caller should make sure to \
+                call `is_complete_body` first",
+                std::any::type_name::<B>(),
+            );
+
+            // we do not have DerefMut access to call take_complete_body directly but since
+            // is_complete_body is true we should expect the entire bytes chunk in one poll_next
+
+            let waker = futures_util::task::noop_waker();
+            let mut cx = Context::from_waker(&waker);
+
+            match self.as_mut().poll_next(&mut cx) {
+                Poll::Ready(Some(Ok(data))) => data,
+                _ => {
+                    panic!(
+                        "inner type \"{}\" indicated it allows taking complete body but failed to \
+                        return Bytes when polled",
+                        std::any::type_name::<B>()
+                    );
+                }
+            }
+        }
    }

    impl MessageBody for &'static [u8] {
        type Error = Infallible;

+        #[inline]
        fn size(&self) -> BodySize {
            BodySize::Sized(self.len() as u64)
        }

        fn poll_next(
-            self: Pin<&mut Self>,
+            mut self: Pin<&mut Self>,
            _cx: &mut Context<'_>,
        ) -> Poll<Option<Result<Bytes, Self::Error>>> {
            if self.is_empty() {
                Poll::Ready(None)
            } else {
-                let bytes = mem::take(self.get_mut());
-                let bytes = Bytes::from_static(bytes);
-                Poll::Ready(Some(Ok(bytes)))
+                Poll::Ready(Some(Ok(self.take_complete_body())))
            }
        }
+
+        #[inline]
+        fn is_complete_body(&self) -> bool {
+            true
+        }
+
+        #[inline]
+        fn take_complete_body(&mut self) -> Bytes {
+            Bytes::from_static(mem::take(self))
+        }
    }

    impl MessageBody for Bytes {
        type Error = Infallible;

+        #[inline]
        fn size(&self) -> BodySize {
            BodySize::Sized(self.len() as u64)
        }

        fn poll_next(
-            self: Pin<&mut Self>,
+            mut self: Pin<&mut Self>,
            _cx: &mut Context<'_>,
        ) -> Poll<Option<Result<Bytes, Self::Error>>> {
            if self.is_empty() {
                Poll::Ready(None)
            } else {
-                let bytes = mem::take(self.get_mut());
-                Poll::Ready(Some(Ok(bytes)))
+                Poll::Ready(Some(Ok(self.take_complete_body())))
            }
        }
+
+        #[inline]
+        fn is_complete_body(&self) -> bool {
+            true
+        }
+
+        #[inline]
+        fn take_complete_body(&mut self) -> Bytes {
+            mem::take(self)
+        }
    }

    impl MessageBody for BytesMut {
        type Error = Infallible;

+        #[inline]
        fn size(&self) -> BodySize {
            BodySize::Sized(self.len() as u64)
        }

        fn poll_next(
-            self: Pin<&mut Self>,
+            mut self: Pin<&mut Self>,
            _cx: &mut Context<'_>,
        ) -> Poll<Option<Result<Bytes, Self::Error>>> {
            if self.is_empty() {
                Poll::Ready(None)
            } else {
-                let bytes = mem::take(self.get_mut()).freeze();
-                Poll::Ready(Some(Ok(bytes)))
+                Poll::Ready(Some(Ok(self.take_complete_body())))
            }
        }
+
+        #[inline]
+        fn is_complete_body(&self) -> bool {
+            true
+        }
+
+        #[inline]
+        fn take_complete_body(&mut self) -> Bytes {
+            mem::take(self).freeze()
+        }
    }

    impl MessageBody for Vec<u8> {
        type Error = Infallible;

+        #[inline]
        fn size(&self) -> BodySize {
            BodySize::Sized(self.len() as u64)
        }

        fn poll_next(
-            self: Pin<&mut Self>,
+            mut self: Pin<&mut Self>,
            _cx: &mut Context<'_>,
        ) -> Poll<Option<Result<Bytes, Self::Error>>> {
            if self.is_empty() {
                Poll::Ready(None)
            } else {
-                let bytes = mem::take(self.get_mut());
-                Poll::Ready(Some(Ok(Bytes::from(bytes))))
+                Poll::Ready(Some(Ok(self.take_complete_body())))
            }
        }
+
+        #[inline]
+        fn is_complete_body(&self) -> bool {
+            true
+        }
+
+        #[inline]
+        fn take_complete_body(&mut self) -> Bytes {
+            Bytes::from(mem::take(self))
+        }
    }

    impl MessageBody for &'static str {
        type Error = Infallible;

+        #[inline]
        fn size(&self) -> BodySize {
            BodySize::Sized(self.len() as u64)
        }
@@ -208,11 +354,22 @@ mod foreign_impls {
                Poll::Ready(Some(Ok(bytes)))
            }
        }
+
+        #[inline]
+        fn is_complete_body(&self) -> bool {
+            true
+        }
+
+        #[inline]
+        fn take_complete_body(&mut self) -> Bytes {
+            Bytes::from_static(mem::take(self).as_bytes())
+        }
    }

    impl MessageBody for String {
        type Error = Infallible;

+        #[inline]
        fn size(&self) -> BodySize {
            BodySize::Sized(self.len() as u64)
        }
@@ -228,11 +385,22 @@ mod foreign_impls {
                Poll::Ready(Some(Ok(Bytes::from(string))))
            }
        }
+
+        #[inline]
+        fn is_complete_body(&self) -> bool {
+            true
+        }
+
+        #[inline]
+        fn take_complete_body(&mut self) -> Bytes {
+            Bytes::from(mem::take(self))
+        }
    }

    impl MessageBody for bytestring::ByteString {
        type Error = Infallible;

+        #[inline]
        fn size(&self) -> BodySize {
            BodySize::Sized(self.len() as u64)
        }
@@ -244,6 +412,16 @@ mod foreign_impls {
            let string = mem::take(self.get_mut());
            Poll::Ready(Some(Ok(string.into_bytes())))
        }
+
+        #[inline]
+        fn is_complete_body(&self) -> bool {
+            true
+        }
+
+        #[inline]
+        fn take_complete_body(&mut self) -> Bytes {
+            mem::take(self).into_bytes()
+        }
    }
 }

@@ -272,10 +450,11 @@ impl<B, F, E> MessageBody for MessageBodyMapErr<B, F>
 where
    B: MessageBody,
    F: FnOnce(B::Error) -> E,
-    E: Into<Box<dyn StdError>> + 'static,
+    E: Into<Box<dyn StdError>>,
 {
    type Error = E;

+    #[inline]
    fn size(&self) -> BodySize {
        self.body.size()
    }
@@ -306,8 +485,6 @@ mod tests {

    use super::*;

-    // static_assertions::assert_obj_safe!(MessageBody<()>);
-
    macro_rules! assert_poll_next {
        ($pin:expr, $exp:expr) => {
            assert_eq!(
@@ -408,6 +585,51 @@ mod tests {
        assert_poll_next!(pl, Bytes::from("test"));
    }

+    #[test]
+    fn take_string() {
+        let mut data = "test".repeat(2);
+        let data_bytes = Bytes::from(data.clone());
+        assert!(data.is_complete_body());
+        assert_eq!(data.take_complete_body(), data_bytes);
+
+        let mut big_data = "test".repeat(64 * 1024);
+        let data_bytes = Bytes::from(big_data.clone());
+        assert!(big_data.is_complete_body());
+        assert_eq!(big_data.take_complete_body(), data_bytes);
+    }
+
+    #[test]
+    fn take_boxed_equivalence() {
+        let mut data = Bytes::from_static(b"test");
+        assert!(data.is_complete_body());
+        assert_eq!(data.take_complete_body(), b"test".as_ref());
+
+        let mut data = Box::new(Bytes::from_static(b"test"));
+        assert!(data.is_complete_body());
+        assert_eq!(data.take_complete_body(), b"test".as_ref());
+
+        let mut data = Box::pin(Bytes::from_static(b"test"));
+        assert!(data.is_complete_body());
+        assert_eq!(data.take_complete_body(), b"test".as_ref());
+    }
+
+    #[test]
+    fn take_policy() {
+        let mut data = Bytes::from_static(b"test");
+        // first call returns chunk
+        assert_eq!(data.take_complete_body(), b"test".as_ref());
+        // second call returns empty
+        assert_eq!(data.take_complete_body(), b"".as_ref());
+
+        let waker = futures_util::task::noop_waker();
+        let mut cx = Context::from_waker(&waker);
+        let mut data = Bytes::from_static(b"test");
+        // take returns whole chunk
+        assert_eq!(data.take_complete_body(), b"test".as_ref());
+        // subsequent poll_next returns None
+        assert_eq!(Pin::new(&mut data).poll_next(&mut cx), Poll::Ready(None));
+    }
+
    // down-casting used to be done with a method on MessageBody trait
    // test is kept to demonstrate equivalence of Any trait
    #[actix_rt::test]
--- a/actix-http/src/body/mod.rs
+++ b/actix-http/src/body/mod.rs
@@ -1,6 +1,5 @@
 //! Traits and structures to aid consuming and writing HTTP payloads.

-// mod any;
 mod body_stream;
 mod boxed;
 mod either;
@@ -10,7 +9,6 @@ mod size;
 mod sized_stream;
 mod utils;

-// pub use self::any::AnyBody;
 pub use self::body_stream::BodyStream;
 pub use self::boxed::BoxBody;
 pub use self::either::EitherBody;
--- a/actix-http/src/body/none.rs
+++ b/actix-http/src/body/none.rs
@@ -40,4 +40,14 @@ impl MessageBody for None {
    ) -> Poll<Option<Result<Bytes, Self::Error>>> {
        Poll::Ready(Option::None)
    }
+
+    #[inline]
+    fn is_complete_body(&self) -> bool {
+        true
+    }
+
+    #[inline]
+    fn take_complete_body(&mut self) -> Bytes {
+        Bytes::new()
+    }
 }
--- a/actix-http/src/body/size.rs
+++ b/actix-http/src/body/size.rs
@@ -1,9 +1,11 @@
 /// Body size hint.
-#[derive(Debug, Clone, Copy, PartialEq)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub enum BodySize {
-    /// Absence of body can be assumed from method or status code.
+    /// Implicitly empty body.
    ///
-    /// Will skip writing Content-Length header.
+    /// Will omit the Content-Length header. Used for responses to certain methods (e.g., `HEAD`) or
+    /// with particular status codes (e.g., 204 No Content). Consumers that read this as a body size
+    /// hint are allowed to make optimizations that skip reading or writing the payload.
    None,

    /// Known size body.
@@ -18,6 +20,9 @@ pub enum BodySize {
 }

 impl BodySize {
+    /// Equivalent to `BodySize::Sized(0)`;
+    pub const ZERO: Self = Self::Sized(0);
+
    /// Returns true if size hint indicates omitted or empty body.
    ///
    /// Streams will return false because it cannot be known without reading the stream.
--- a/actix-http/src/body/sized_stream.rs
+++ b/actix-http/src/body/sized_stream.rs
@@ -27,6 +27,7 @@ where
    S: Stream<Item = Result<Bytes, E>>,
    E: Into<Box<dyn StdError>> + 'static,
 {
+    #[inline]
    pub fn new(size: u64, stream: S) -> Self {
        SizedStream { size, stream }
    }
@@ -41,6 +42,7 @@ where
 {
    type Error = E;

+    #[inline]
    fn size(&self) -> BodySize {
        BodySize::Sized(self.size as u64)
    }
--- a/actix-http/src/encoding/encoder.rs
+++ b/actix-http/src/encoding/encoder.rs
@@ -1,6 +1,7 @@
 //! Stream encoders.

 use std::{
+    error::Error as StdError,
    future::Future,
    io::{self, Write as _},
    pin::Pin,
@@ -9,6 +10,7 @@ use std::{

 use actix_rt::task::{spawn_blocking, JoinHandle};
 use bytes::Bytes;
+use derive_more::Display;
 use futures_core::ready;
 use pin_project_lite::pin_project;

@@ -21,7 +23,7 @@ use flate2::write::{GzEncoder, ZlibEncoder};
 #[cfg(feature = "compress-zstd")]
 use zstd::stream::write::Encoder as ZstdEncoder;

-use super::{EncoderError, Writer};
+use super::Writer;
 use crate::{
    body::{BodySize, MessageBody},
    error::BlockingError,
@@ -51,41 +53,32 @@ impl<B: MessageBody> Encoder<B> {
        }
    }

-    pub fn not_acceptable(body: Bytes) -> Self {
-        Encoder {
-            body: EncoderBody::Bytes { body },
-            encoder: None,
-            fut: None,
-            eof: false,
-        }
-    }
-
-    pub fn response(encoding: ContentEncoding, head: &mut ResponseHead, body: B) -> Self {
+    pub fn response(encoding: ContentEncoding, head: &mut ResponseHead, mut body: B) -> Self {
        let can_encode = !(head.headers().contains_key(&CONTENT_ENCODING)
            || head.status == StatusCode::SWITCHING_PROTOCOLS
            || head.status == StatusCode::NO_CONTENT
            || encoding == ContentEncoding::Identity
            || encoding == ContentEncoding::Auto);

-        match body.size() {
-            // no need to compress an empty body
-            BodySize::None => return Self::none(),
-
-            // we cannot assume that Sized is not a stream
-            BodySize::Sized(_) | BodySize::Stream => {}
+        // no need to compress an empty body
+        if matches!(body.size(), BodySize::None) {
+            return Self::none();
        }

-        // TODO potentially some optimisation for single-chunk responses here by trying to read the
-        // payload eagerly, stopping after 2 polls if the first is a chunk and the second is None
+        let body = if body.is_complete_body() {
+            let body = body.take_complete_body();
+            EncoderBody::Full { body }
+        } else {
+            EncoderBody::Stream { body }
+        };

        if can_encode {
            // Modify response body only if encoder is set
            if let Some(enc) = ContentEncoder::encoder(encoding) {
                update_head(encoding, head);
-                head.no_chunking(false);

                return Encoder {
-                    body: EncoderBody::Stream { body },
+                    body,
                    encoder: Some(enc),
                    fut: None,
                    eof: false,
@@ -94,7 +87,7 @@ impl<B: MessageBody> Encoder<B> {
        }

        Encoder {
-            body: EncoderBody::Stream { body },
+            body,
            encoder: None,
            fut: None,
            eof: false,
@@ -106,7 +99,7 @@ pin_project! {
    #[project = EncoderBodyProj]
    enum EncoderBody<B> {
        None,
-        Bytes { body: Bytes },
+        Full { body: Bytes },
        Stream { #[pin] body: B },
    }
 }
@@ -120,7 +113,7 @@ where
    fn size(&self) -> BodySize {
        match self {
            EncoderBody::None => BodySize::None,
-            EncoderBody::Bytes { body } => body.size(),
+            EncoderBody::Full { body } => body.size(),
            EncoderBody::Stream { body } => body.size(),
        }
    }
@@ -131,7 +124,7 @@ where
    ) -> Poll<Option<Result<Bytes, Self::Error>>> {
        match self.project() {
            EncoderBodyProj::None => Poll::Ready(None),
-            EncoderBodyProj::Bytes { body } => {
+            EncoderBodyProj::Full { body } => {
                Pin::new(body).poll_next(cx).map_err(|err| match err {})
            }
            EncoderBodyProj::Stream { body } => body
@@ -139,6 +132,24 @@ where
                .map_err(|err| EncoderError::Body(err.into())),
        }
    }
+
+    fn is_complete_body(&self) -> bool {
+        match self {
+            EncoderBody::None => true,
+            EncoderBody::Full { .. } => true,
+            EncoderBody::Stream { .. } => false,
+        }
+    }
+
+    fn take_complete_body(&mut self) -> Bytes {
+        match self {
+            EncoderBody::None => Bytes::new(),
+            EncoderBody::Full { body } => body.take_complete_body(),
+            EncoderBody::Stream { .. } => {
+                panic!("EncoderBody::Stream variant cannot be taken")
+            }
+        }
+    }
 }

 impl<B> MessageBody for Encoder<B>
@@ -148,10 +159,10 @@ where
    type Error = EncoderError;

    fn size(&self) -> BodySize {
-        if self.encoder.is_none() {
-            self.body.size()
-        } else {
+        if self.encoder.is_some() {
            BodySize::Stream
+        } else {
+            self.body.size()
        }
    }

@@ -222,6 +233,22 @@ where
            }
        }
    }
+
+    fn is_complete_body(&self) -> bool {
+        if self.encoder.is_some() {
+            false
+        } else {
+            self.body.is_complete_body()
+        }
+    }
+
+    fn take_complete_body(&mut self) -> Bytes {
+        if self.encoder.is_some() {
+            panic!("compressed body stream cannot be taken")
+        } else {
+            self.body.take_complete_body()
+        }
+    }
 }

 fn update_head(encoding: ContentEncoding, head: &mut ResponseHead) {
@@ -229,6 +256,8 @@ fn update_head(encoding: ContentEncoding, head: &mut ResponseHead) {
        header::CONTENT_ENCODING,
        HeaderValue::from_static(encoding.as_str()),
    );
+
+    head.no_chunking(false);
 }

 enum ContentEncoder {
@@ -362,3 +391,32 @@ impl ContentEncoder {
        }
    }
 }
+
+#[derive(Debug, Display)]
+#[non_exhaustive]
+pub enum EncoderError {
+    #[display(fmt = "body")]
+    Body(Box<dyn StdError>),
+
+    #[display(fmt = "blocking")]
+    Blocking(BlockingError),
+
+    #[display(fmt = "io")]
+    Io(io::Error),
+}
+
+impl StdError for EncoderError {
+    fn source(&self) -> Option<&(dyn StdError + 'static)> {
+        match self {
+            EncoderError::Body(err) => Some(&**err),
+            EncoderError::Blocking(err) => Some(err),
+            EncoderError::Io(err) => Some(err),
+        }
+    }
+}
+
+impl From<EncoderError> for crate::Error {
+    fn from(err: EncoderError) -> Self {
+        crate::Error::new_encoder().with_cause(err)
+    }
+}
--- a/actix-http/src/encoding/mod.rs
+++ b/actix-http/src/encoding/mod.rs
@@ -1,60 +1,22 @@
 //! Content-Encoding support.

-use std::{error::Error as StdError, io};
+use std::io;

 use bytes::{Bytes, BytesMut};
-use derive_more::Display;

-use crate::error::BlockingError;
-
-#[cfg(feature = "__compress")]
 mod decoder;
-#[cfg(feature = "__compress")]
 mod encoder;

-#[cfg(feature = "__compress")]
 pub use self::decoder::Decoder;
-#[cfg(feature = "__compress")]
 pub use self::encoder::Encoder;

-#[derive(Debug, Display)]
-#[non_exhaustive]
-pub enum EncoderError {
-    #[display(fmt = "body")]
-    Body(Box<dyn StdError>),
-
-    #[display(fmt = "blocking")]
-    Blocking(BlockingError),
-
-    #[display(fmt = "io")]
-    Io(io::Error),
-}
-
-impl StdError for EncoderError {
-    fn source(&self) -> Option<&(dyn StdError + 'static)> {
-        match self {
-            EncoderError::Body(err) => Some(&**err),
-            EncoderError::Blocking(err) => Some(err),
-            EncoderError::Io(err) => Some(err),
-        }
-    }
-}
-
-impl From<EncoderError> for crate::Error {
-    fn from(err: EncoderError) -> Self {
-        crate::Error::new_encoder().with_cause(err)
-    }
-}
-
 /// Special-purpose writer for streaming (de-)compression.
 ///
 /// Pre-allocates 8KiB of capacity.
-#[cfg(feature = "__compress")]
 pub(self) struct Writer {
    buf: BytesMut,
 }

-#[cfg(feature = "__compress")]
 impl Writer {
    fn new() -> Writer {
        Writer {
@@ -67,7 +29,6 @@ impl Writer {
    }
 }

-#[cfg(feature = "__compress")]
 impl io::Write for Writer {
    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
        self.buf.extend_from_slice(buf);
--- a/actix-http/src/error.rs
+++ b/actix-http/src/error.rs
@@ -9,8 +9,6 @@ use crate::{body::BoxBody, ws, Response};

 pub use http::Error as HttpError;

-pub use crate::encoding::EncoderError;
-
 pub struct Error {
    inner: Box<ErrorInner>,
 }
--- a/actix-http/src/h2/dispatcher.rs
+++ b/actix-http/src/h2/dispatcher.rs
@@ -19,13 +19,13 @@ use h2::{
    server::{Connection, SendResponse},
    Ping, PingPong,
 };
-use http::header::{HeaderValue, CONNECTION, CONTENT_LENGTH, DATE, TRANSFER_ENCODING};
 use log::{error, trace};
 use pin_project_lite::pin_project;

 use crate::{
    body::{BodySize, BoxBody, MessageBody},
    config::ServiceConfig,
+    header::{HeaderValue, CONNECTION, CONTENT_LENGTH, DATE, TRANSFER_ENCODING},
    service::HttpFlow,
    Extensions, OnConnectData, Payload, Request, Response, ResponseHead,
 };
@@ -217,25 +217,28 @@ where
        return Ok(());
    }

-    // poll response body and send chunks to client.
+    // poll response body and send chunks to client
    actix_rt::pin!(body);

    while let Some(res) = poll_fn(|cx| body.as_mut().poll_next(cx)).await {
        let mut chunk = res.map_err(|err| DispatchError::ResponseBody(err.into()))?;

        'send: loop {
+            let chunk_size = cmp::min(chunk.len(), CHUNK_SIZE);
+
            // reserve enough space and wait for stream ready.
-            stream.reserve_capacity(cmp::min(chunk.len(), CHUNK_SIZE));
+            stream.reserve_capacity(chunk_size);

            match poll_fn(|cx| stream.poll_capacity(cx)).await {
                // No capacity left. drop body and return.
                None => return Ok(()),
-                Some(res) => {
-                    // Split chuck to writeable size and send to client.
-                    let cap = res.map_err(DispatchError::SendData)?;

+                Some(Err(err)) => return Err(DispatchError::SendData(err)),
+
+                Some(Ok(cap)) => {
+                    // split chunk to writeable size and send to client
                    let len = chunk.len();
-                    let bytes = chunk.split_to(cmp::min(cap, len));
+                    let bytes = chunk.split_to(cmp::min(len, cap));

                    stream
                        .send_data(bytes, false)
--- a/actix-http/src/h2/service.rs
+++ b/actix-http/src/h2/service.rs
@@ -270,10 +270,10 @@ where
    type Future = H2ServiceHandlerResponse<T, S, B>;

    fn poll_ready(&self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
-        self.flow.service.poll_ready(cx).map_err(|e| {
-            let e = e.into();
-            error!("Service readiness error: {:?}", e);
-            DispatchError::Service(e)
+        self.flow.service.poll_ready(cx).map_err(|err| {
+            let err = err.into();
+            error!("Service readiness error: {:?}", err);
+            DispatchError::Service(err)
        })
    }

@@ -297,7 +297,6 @@ where
    T: AsyncRead + AsyncWrite + Unpin,
    S::Future: 'static,
 {
-    Incoming(Dispatcher<T, S, B, (), ()>),
    Handshake(
        Option<Rc<HttpFlow<S, (), ()>>>,
        Option<ServiceConfig>,
@@ -305,6 +304,7 @@ where
        OnConnectData,
        HandshakeWithTimeout<T>,
    ),
+    Established(Dispatcher<T, S, B, (), ()>),
 }

 pub struct H2ServiceHandlerResponse<T, S, B>
@@ -332,7 +332,6 @@ where

    fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
        match self.state {
-            State::Incoming(ref mut disp) => Pin::new(disp).poll(cx),
            State::Handshake(
                ref mut srv,
                ref mut config,
@@ -343,7 +342,7 @@ where
                Ok((conn, timer)) => {
                    let on_connect_data = mem::take(conn_data);

-                    self.state = State::Incoming(Dispatcher::new(
+                    self.state = State::Established(Dispatcher::new(
                        conn,
                        srv.take().unwrap(),
                        config.take().unwrap(),
@@ -360,6 +359,8 @@ where
                    Poll::Ready(Err(err))
                }
            },
+
+            State::Established(ref mut disp) => Pin::new(disp).poll(cx),
        }
    }
 }
--- a/actix-http/src/header/as_name.rs
+++ b/actix-http/src/header/as_name.rs
@@ -16,6 +16,7 @@ pub trait Sealed {
 }

 impl Sealed for HeaderName {
+    #[inline]
    fn try_as_name(&self, _: Seal) -> Result<Cow<'_, HeaderName>, InvalidHeaderName> {
        Ok(Cow::Borrowed(self))
    }
@@ -23,6 +24,7 @@ impl Sealed for HeaderName {
 impl AsHeaderName for HeaderName {}

 impl Sealed for &HeaderName {
+    #[inline]
    fn try_as_name(&self, _: Seal) -> Result<Cow<'_, HeaderName>, InvalidHeaderName> {
        Ok(Cow::Borrowed(*self))
    }
@@ -30,6 +32,7 @@ impl Sealed for &HeaderName {
 impl AsHeaderName for &HeaderName {}

 impl Sealed for &str {
+    #[inline]
    fn try_as_name(&self, _: Seal) -> Result<Cow<'_, HeaderName>, InvalidHeaderName> {
        HeaderName::from_str(self).map(Cow::Owned)
    }
@@ -37,6 +40,7 @@ impl Sealed for &str {
 impl AsHeaderName for &str {}

 impl Sealed for String {
+    #[inline]
    fn try_as_name(&self, _: Seal) -> Result<Cow<'_, HeaderName>, InvalidHeaderName> {
        HeaderName::from_str(self).map(Cow::Owned)
    }
@@ -44,6 +48,7 @@ impl Sealed for String {
 impl AsHeaderName for String {}

 impl Sealed for &String {
+    #[inline]
    fn try_as_name(&self, _: Seal) -> Result<Cow<'_, HeaderName>, InvalidHeaderName> {
        HeaderName::from_str(self).map(Cow::Owned)
    }
--- a/actix-http/src/header/into_pair.rs
+++ b/actix-http/src/header/into_pair.rs
@@ -1,22 +1,20 @@
-//! [`IntoHeaderPair`] trait and implementations.
+//! [`TryIntoHeaderPair`] trait and implementations.

 use std::convert::TryFrom as _;

-use http::{
-    header::{HeaderName, InvalidHeaderName, InvalidHeaderValue},
-    Error as HttpError, HeaderValue,
+use super::{
+    Header, HeaderName, HeaderValue, InvalidHeaderName, InvalidHeaderValue, TryIntoHeaderValue,
 };
+use crate::error::HttpError;

-use super::{Header, IntoHeaderValue};
-
-/// An interface for types that can be converted into a [`HeaderName`]/[`HeaderValue`] pair for
+/// An interface for types that can be converted into a [`HeaderName`] + [`HeaderValue`] pair for
 /// insertion into a [`HeaderMap`].
 ///
 /// [`HeaderMap`]: super::HeaderMap
-pub trait IntoHeaderPair: Sized {
+pub trait TryIntoHeaderPair: Sized {
    type Error: Into<HttpError>;

-    fn try_into_header_pair(self) -> Result<(HeaderName, HeaderValue), Self::Error>;
+    fn try_into_pair(self) -> Result<(HeaderName, HeaderValue), Self::Error>;
 }

 #[derive(Debug)]
@@ -34,14 +32,14 @@ impl From<InvalidHeaderPart> for HttpError {
    }
 }

-impl<V> IntoHeaderPair for (HeaderName, V)
+impl<V> TryIntoHeaderPair for (HeaderName, V)
 where
-    V: IntoHeaderValue,
+    V: TryIntoHeaderValue,
    V::Error: Into<InvalidHeaderValue>,
 {
    type Error = InvalidHeaderPart;

-    fn try_into_header_pair(self) -> Result<(HeaderName, HeaderValue), Self::Error> {
+    fn try_into_pair(self) -> Result<(HeaderName, HeaderValue), Self::Error> {
        let (name, value) = self;
        let value = value
            .try_into_value()
@@ -50,14 +48,14 @@ where
    }
 }

-impl<V> IntoHeaderPair for (&HeaderName, V)
+impl<V> TryIntoHeaderPair for (&HeaderName, V)
 where
-    V: IntoHeaderValue,
+    V: TryIntoHeaderValue,
    V::Error: Into<InvalidHeaderValue>,
 {
    type Error = InvalidHeaderPart;

-    fn try_into_header_pair(self) -> Result<(HeaderName, HeaderValue), Self::Error> {
+    fn try_into_pair(self) -> Result<(HeaderName, HeaderValue), Self::Error> {
        let (name, value) = self;
        let value = value
            .try_into_value()
@@ -66,14 +64,14 @@ where
    }
 }

-impl<V> IntoHeaderPair for (&[u8], V)
+impl<V> TryIntoHeaderPair for (&[u8], V)
 where
-    V: IntoHeaderValue,
+    V: TryIntoHeaderValue,
    V::Error: Into<InvalidHeaderValue>,
 {
    type Error = InvalidHeaderPart;

-    fn try_into_header_pair(self) -> Result<(HeaderName, HeaderValue), Self::Error> {
+    fn try_into_pair(self) -> Result<(HeaderName, HeaderValue), Self::Error> {
        let (name, value) = self;
        let name = HeaderName::try_from(name).map_err(InvalidHeaderPart::Name)?;
        let value = value
@@ -83,14 +81,14 @@ where
    }
 }

-impl<V> IntoHeaderPair for (&str, V)
+impl<V> TryIntoHeaderPair for (&str, V)
 where
-    V: IntoHeaderValue,
+    V: TryIntoHeaderValue,
    V::Error: Into<InvalidHeaderValue>,
 {
    type Error = InvalidHeaderPart;

-    fn try_into_header_pair(self) -> Result<(HeaderName, HeaderValue), Self::Error> {
+    fn try_into_pair(self) -> Result<(HeaderName, HeaderValue), Self::Error> {
        let (name, value) = self;
        let name = HeaderName::try_from(name).map_err(InvalidHeaderPart::Name)?;
        let value = value
@@ -100,23 +98,25 @@ where
    }
 }

-impl<V> IntoHeaderPair for (String, V)
+impl<V> TryIntoHeaderPair for (String, V)
 where
-    V: IntoHeaderValue,
+    V: TryIntoHeaderValue,
    V::Error: Into<InvalidHeaderValue>,
 {
    type Error = InvalidHeaderPart;

-    fn try_into_header_pair(self) -> Result<(HeaderName, HeaderValue), Self::Error> {
+    #[inline]
+    fn try_into_pair(self) -> Result<(HeaderName, HeaderValue), Self::Error> {
        let (name, value) = self;
-        (name.as_str(), value).try_into_header_pair()
+        (name.as_str(), value).try_into_pair()
    }
 }

-impl<T: Header> IntoHeaderPair for T {
-    type Error = <T as IntoHeaderValue>::Error;
+impl<T: Header> TryIntoHeaderPair for T {
+    type Error = <T as TryIntoHeaderValue>::Error;

-    fn try_into_header_pair(self) -> Result<(HeaderName, HeaderValue), Self::Error> {
+    #[inline]
+    fn try_into_pair(self) -> Result<(HeaderName, HeaderValue), Self::Error> {
        Ok((T::name(), self.try_into_value()?))
    }
 }
--- a/actix-http/src/header/into_value.rs
+++ b/actix-http/src/header/into_value.rs
@@ -1,4 +1,4 @@
-//! [`IntoHeaderValue`] trait and implementations.
+//! [`TryIntoHeaderValue`] trait and implementations.

 use std::convert::TryFrom as _;

@@ -7,7 +7,7 @@ use http::{header::InvalidHeaderValue, Error as HttpError, HeaderValue};
 use mime::Mime;

 /// An interface for types that can be converted into a [`HeaderValue`].
-pub trait IntoHeaderValue: Sized {
+pub trait TryIntoHeaderValue: Sized {
    /// The type returned in the event of a conversion error.
    type Error: Into<HttpError>;

@@ -15,7 +15,7 @@ pub trait IntoHeaderValue: Sized {
    fn try_into_value(self) -> Result<HeaderValue, Self::Error>;
 }

-impl IntoHeaderValue for HeaderValue {
+impl TryIntoHeaderValue for HeaderValue {
    type Error = InvalidHeaderValue;

    #[inline]
@@ -24,7 +24,7 @@ impl IntoHeaderValue for HeaderValue {
    }
 }

-impl IntoHeaderValue for &HeaderValue {
+impl TryIntoHeaderValue for &HeaderValue {
    type Error = InvalidHeaderValue;

    #[inline]
@@ -33,7 +33,7 @@ impl IntoHeaderValue for &HeaderValue {
    }
 }

-impl IntoHeaderValue for &str {
+impl TryIntoHeaderValue for &str {
    type Error = InvalidHeaderValue;

    #[inline]
@@ -42,7 +42,7 @@ impl IntoHeaderValue for &str {
    }
 }

-impl IntoHeaderValue for &[u8] {
+impl TryIntoHeaderValue for &[u8] {
    type Error = InvalidHeaderValue;

    #[inline]
@@ -51,7 +51,7 @@ impl IntoHeaderValue for &[u8] {
    }
 }

-impl IntoHeaderValue for Bytes {
+impl TryIntoHeaderValue for Bytes {
    type Error = InvalidHeaderValue;

    #[inline]
@@ -60,7 +60,7 @@ impl IntoHeaderValue for Bytes {
    }
 }

-impl IntoHeaderValue for Vec<u8> {
+impl TryIntoHeaderValue for Vec<u8> {
    type Error = InvalidHeaderValue;

    #[inline]
@@ -69,7 +69,7 @@ impl IntoHeaderValue for Vec<u8> {
    }
 }

-impl IntoHeaderValue for String {
+impl TryIntoHeaderValue for String {
    type Error = InvalidHeaderValue;

    #[inline]
@@ -78,7 +78,7 @@ impl IntoHeaderValue for String {
    }
 }

-impl IntoHeaderValue for usize {
+impl TryIntoHeaderValue for usize {
    type Error = InvalidHeaderValue;

    #[inline]
@@ -87,7 +87,7 @@ impl IntoHeaderValue for usize {
    }
 }

-impl IntoHeaderValue for i64 {
+impl TryIntoHeaderValue for i64 {
    type Error = InvalidHeaderValue;

    #[inline]
@@ -96,7 +96,7 @@ impl IntoHeaderValue for i64 {
    }
 }

-impl IntoHeaderValue for u64 {
+impl TryIntoHeaderValue for u64 {
    type Error = InvalidHeaderValue;

    #[inline]
@@ -105,7 +105,7 @@ impl IntoHeaderValue for u64 {
    }
 }

-impl IntoHeaderValue for i32 {
+impl TryIntoHeaderValue for i32 {
    type Error = InvalidHeaderValue;

    #[inline]
@@ -114,7 +114,7 @@ impl IntoHeaderValue for i32 {
    }
 }

-impl IntoHeaderValue for u32 {
+impl TryIntoHeaderValue for u32 {
    type Error = InvalidHeaderValue;

    #[inline]
@@ -123,7 +123,7 @@ impl IntoHeaderValue for u32 {
    }
 }

-impl IntoHeaderValue for Mime {
+impl TryIntoHeaderValue for Mime {
    type Error = InvalidHeaderValue;

    #[inline]
--- a/actix-http/src/header/map.rs
+++ b/actix-http/src/header/map.rs
@@ -333,7 +333,7 @@ impl HeaderMap {
        }
    }

-    /// Inserts a name-value pair into the map.
+    /// Inserts (overrides) a name-value pair in the map.
    ///
    /// If the map already contained this key, the new value is associated with the key and all
    /// previous values are removed and returned as a `Removed` iterator. The key is not updated;
@@ -372,7 +372,7 @@ impl HeaderMap {
        Removed::new(value)
    }

-    /// Inserts a name-value pair into the map.
+    /// Appends a name-value pair to the map.
    ///
    /// If the map already contained this key, the new value is added to the list of values
    /// currently associated with the key. The key is not updated; this matters for types that can
--- a/actix-http/src/header/mod.rs
+++ b/actix-http/src/header/mod.rs
@@ -37,8 +37,8 @@ mod shared;
 mod utils;

 pub use self::as_name::AsHeaderName;
-pub use self::into_pair::IntoHeaderPair;
-pub use self::into_value::IntoHeaderValue;
+pub use self::into_pair::TryIntoHeaderPair;
+pub use self::into_value::TryIntoHeaderValue;
 pub use self::map::HeaderMap;
 pub use self::shared::{
    parse_extended_value, q, Charset, ContentEncoding, ExtendedValue, HttpDate, LanguageTag,
@@ -49,7 +49,7 @@ pub use self::utils::{
 };

 /// An interface for types that already represent a valid header.
-pub trait Header: IntoHeaderValue {
+pub trait Header: TryIntoHeaderValue {
    /// Returns the name of the header field
    fn name() -> HeaderName;

--- a/actix-http/src/header/shared/content_encoding.rs
+++ b/actix-http/src/header/shared/content_encoding.rs
@@ -5,7 +5,7 @@ use http::header::InvalidHeaderValue;

 use crate::{
    error::ParseError,
-    header::{self, from_one_raw_str, Header, HeaderName, HeaderValue, IntoHeaderValue},
+    header::{self, from_one_raw_str, Header, HeaderName, HeaderValue, TryIntoHeaderValue},
    HttpMessage,
 };

@@ -96,7 +96,7 @@ impl TryFrom<&str> for ContentEncoding {
    }
 }

-impl IntoHeaderValue for ContentEncoding {
+impl TryIntoHeaderValue for ContentEncoding {
    type Error = InvalidHeaderValue;

    fn try_into_value(self) -> Result<http::HeaderValue, Self::Error> {
--- a/actix-http/src/header/shared/http_date.rs
+++ b/actix-http/src/header/shared/http_date.rs
@@ -4,7 +4,8 @@ use bytes::BytesMut;
 use http::header::{HeaderValue, InvalidHeaderValue};

 use crate::{
-    config::DATE_VALUE_LENGTH, error::ParseError, header::IntoHeaderValue, helpers::MutWriter,
+    config::DATE_VALUE_LENGTH, error::ParseError, header::TryIntoHeaderValue,
+    helpers::MutWriter,
 };

 /// A timestamp with HTTP-style formatting and parsing.
@@ -29,7 +30,7 @@ impl fmt::Display for HttpDate {
    }
 }

-impl IntoHeaderValue for HttpDate {
+impl TryIntoHeaderValue for HttpDate {
    type Error = InvalidHeaderValue;

    fn try_into_value(self) -> Result<HeaderValue, Self::Error> {
--- a/actix-http/src/lib.rs
+++ b/actix-http/src/lib.rs
@@ -32,6 +32,7 @@ pub mod body;
 mod builder;
 mod config;

+#[cfg(feature = "__compress")]
 pub mod encoding;
 mod extensions;
 pub mod header;
--- a/actix-http/src/payload.rs
+++ b/actix-http/src/payload.rs
@@ -7,10 +7,10 @@ use h2::RecvStream;

 use crate::error::PayloadError;

-/// Type represent boxed payload
+/// A boxed payload.
 pub type PayloadStream = Pin<Box<dyn Stream<Item = Result<Bytes, PayloadError>>>>;

-/// Type represent streaming payload
+/// A streaming payload.
 pub enum Payload<S = PayloadStream> {
    None,
    H1(crate::h1::Payload),
--- a/actix-http/src/response.rs
+++ b/actix-http/src/response.rs
@@ -2,7 +2,7 @@

 use std::{
    cell::{Ref, RefMut},
-    fmt, mem, str,
+    fmt, str,
 };

 use bytes::{Bytes, BytesMut};
@@ -11,7 +11,7 @@ use bytestring::ByteString;
 use crate::{
    body::{BoxBody, MessageBody},
    extensions::Extensions,
-    header::{self, HeaderMap, IntoHeaderValue},
+    header::{self, HeaderMap, TryIntoHeaderValue},
    message::{BoxedResponseHead, ResponseHead},
    Error, ResponseBuilder, StatusCode,
 };
@@ -203,12 +203,6 @@ impl<B> Response<B> {
    }
 }

-impl<B: Default> Response<B> {
-    pub fn take_body(&mut self) -> B {
-        mem::take(&mut self.body)
-    }
-}
-
 impl<B> fmt::Debug for Response<B>
 where
    B: MessageBody,
--- a/actix-http/src/response_builder.rs
+++ b/actix-http/src/response_builder.rs
@@ -8,7 +8,7 @@ use std::{
 use crate::{
    body::{EitherBody, MessageBody},
    error::{Error, HttpError},
-    header::{self, IntoHeaderPair, IntoHeaderValue},
+    header::{self, TryIntoHeaderPair, TryIntoHeaderValue},
    message::{BoxedResponseHead, ConnectionType, ResponseHead},
    Extensions, Response, StatusCode,
 };
@@ -90,12 +90,9 @@ impl ResponseBuilder {
    /// assert!(res.headers().contains_key("content-type"));
    /// assert!(res.headers().contains_key("x-test"));
    /// ```
-    pub fn insert_header<H>(&mut self, header: H) -> &mut Self
-    where
-        H: IntoHeaderPair,
-    {
+    pub fn insert_header(&mut self, header: impl TryIntoHeaderPair) -> &mut Self {
        if let Some(parts) = self.inner() {
-            match header.try_into_header_pair() {
+            match header.try_into_pair() {
                Ok((key, value)) => {
                    parts.headers.insert(key, value);
                }
@@ -121,12 +118,9 @@ impl ResponseBuilder {
    /// assert_eq!(res.headers().get_all("content-type").count(), 1);
    /// assert_eq!(res.headers().get_all("x-test").count(), 2);
    /// ```
-    pub fn append_header<H>(&mut self, header: H) -> &mut Self
-    where
-        H: IntoHeaderPair,
-    {
+    pub fn append_header(&mut self, header: impl TryIntoHeaderPair) -> &mut Self {
        if let Some(parts) = self.inner() {
-            match header.try_into_header_pair() {
+            match header.try_into_pair() {
                Ok((key, value)) => parts.headers.append(key, value),
                Err(e) => self.err = Some(e.into()),
            };
@@ -157,7 +151,7 @@ impl ResponseBuilder {
    #[inline]
    pub fn upgrade<V>(&mut self, value: V) -> &mut Self
    where
-        V: IntoHeaderValue,
+        V: TryIntoHeaderValue,
    {
        if let Some(parts) = self.inner() {
            parts.set_connection_type(ConnectionType::Upgrade);
@@ -195,7 +189,7 @@ impl ResponseBuilder {
    #[inline]
    pub fn content_type<V>(&mut self, value: V) -> &mut Self
    where
-        V: IntoHeaderValue,
+        V: TryIntoHeaderValue,
    {
        if let Some(parts) = self.inner() {
            match value.try_into_value() {
--- a/actix-http/src/test.rs
+++ b/actix-http/src/test.rs
@@ -14,7 +14,7 @@ use bytes::{Bytes, BytesMut};
 use http::{Method, Uri, Version};

 use crate::{
-    header::{HeaderMap, IntoHeaderPair},
+    header::{HeaderMap, TryIntoHeaderPair},
    payload::Payload,
    Request,
 };
@@ -92,11 +92,8 @@ impl TestRequest {
    }

    /// Insert a header, replacing any that were set with an equivalent field name.
-    pub fn insert_header<H>(&mut self, header: H) -> &mut Self
-    where
-        H: IntoHeaderPair,
-    {
-        match header.try_into_header_pair() {
+    pub fn insert_header(&mut self, header: impl TryIntoHeaderPair) -> &mut Self {
+        match header.try_into_pair() {
            Ok((key, value)) => {
                parts(&mut self.0).headers.insert(key, value);
            }
@@ -109,11 +106,8 @@ impl TestRequest {
    }

    /// Append a header, keeping any that were set with an equivalent field name.
-    pub fn append_header<H>(&mut self, header: H) -> &mut Self
-    where
-        H: IntoHeaderPair,
-    {
-        match header.try_into_header_pair() {
+    pub fn append_header(&mut self, header: impl TryIntoHeaderPair) -> &mut Self {
+        match header.try_into_pair() {
            Ok((key, value)) => {
                parts(&mut self.0).headers.append(key, value);
            }
--- a/actix-http/tests/test_openssl.rs
+++ b/actix-http/tests/test_openssl.rs
@@ -101,7 +101,7 @@ async fn test_h2_1() -> io::Result<()> {

 #[actix_rt::test]
 async fn test_h2_body() -> io::Result<()> {
-    let data = "HELLOWORLD".to_owned().repeat(64 * 1024);
+    let data = "HELLOWORLD".to_owned().repeat(64 * 1024); // 640 KiB
    let mut srv = test_server(move || {
        HttpService::build()
            .h2(|mut req: Request<_>| async move {
--- a/actix-multipart/CHANGES.md
+++ b/actix-multipart/CHANGES.md
@@ -3,6 +3,10 @@
 ## Unreleased - 2021-xx-xx


+## 0.4.0-beta.10 - 2021-12-11
+* No significant changes since `0.4.0-beta.9`.
+
+
 ## 0.4.0-beta.9 - 2021-12-01
 * Polling `Field` after dropping `Multipart` now fails immediately instead of hanging forever. [#2463]

--- a/actix-multipart/Cargo.toml
+++ b/actix-multipart/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "actix-multipart"
-version = "0.4.0-beta.9"
+version = "0.4.0-beta.10"
 authors = ["Nikolay Kim <fafhrd91@gmail.com>"]
 description = "Multipart form support for Actix Web"
 keywords = ["http", "web", "framework", "async", "futures"]
@@ -14,8 +14,8 @@ name = "actix_multipart"
 path = "src/lib.rs"

 [dependencies]
-actix-web = { version = "4.0.0-beta.11", default-features = false }
 actix-utils = "3.0.0"
+actix-web = { version = "4.0.0-beta.14", default-features = false }

 bytes = "1"
 derive_more = "0.99.5"
@@ -28,7 +28,7 @@ twoway = "0.2"

 [dev-dependencies]
 actix-rt = "2.2"
-actix-http = "3.0.0-beta.14"
+actix-http = "3.0.0-beta.15"
 futures-util = { version = "0.3.7", default-features = false, features = ["alloc"] }
 tokio = { version = "1", features = ["sync"] }
 tokio-stream = "0.1"
--- a/actix-multipart/README.md
+++ b/actix-multipart/README.md
@@ -3,11 +3,11 @@
 > Multipart form support for Actix Web.

 [![crates.io](https://img.shields.io/crates/v/actix-multipart?label=latest)](https://crates.io/crates/actix-multipart)
-[![Documentation](https://docs.rs/actix-multipart/badge.svg?version=0.4.0-beta.9)](https://docs.rs/actix-multipart/0.4.0-beta.9)
+[![Documentation](https://docs.rs/actix-multipart/badge.svg?version=0.4.0-beta.10)](https://docs.rs/actix-multipart/0.4.0-beta.10)
 [![Version](https://img.shields.io/badge/rustc-1.52+-ab6000.svg)](https://blog.rust-lang.org/2021/05/06/Rust-1.52.0.html)
 ![MIT or Apache 2.0 licensed](https://img.shields.io/crates/l/actix-multipart.svg)
 <br />
-[![dependency status](https://deps.rs/crate/actix-multipart/0.4.0-beta.9/status.svg)](https://deps.rs/crate/actix-multipart/0.4.0-beta.9)
+[![dependency status](https://deps.rs/crate/actix-multipart/0.4.0-beta.10/status.svg)](https://deps.rs/crate/actix-multipart/0.4.0-beta.10)
 [![Download](https://img.shields.io/crates/d/actix-multipart.svg)](https://crates.io/crates/actix-multipart)
 [![Chat on Discord](https://img.shields.io/discord/771444961383153695?label=chat&logo=discord)](https://discord.gg/NWpN5mmg3x)

--- a/actix-router/src/lib.rs
+++ b/actix-router/src/lib.rs
@@ -7,144 +7,20 @@

 mod de;
 mod path;
+mod pattern;
 mod resource;
+mod resource_path;
 mod router;

-pub use self::de::PathDeserializer;
-pub use self::path::Path;
-pub use self::resource::ResourceDef;
-pub use self::router::{ResourceInfo, Router, RouterBuilder};
-
-// TODO: this trait is necessary, document it
-// see impl Resource for ServiceRequest
-pub trait Resource<T: ResourcePath> {
-    fn resource_path(&mut self) -> &mut Path<T>;
-}
-
-pub trait ResourcePath {
-    fn path(&self) -> &str;
-}
-
-impl ResourcePath for String {
-    fn path(&self) -> &str {
-        self.as_str()
-    }
-}
-
-impl<'a> ResourcePath for &'a str {
-    fn path(&self) -> &str {
-        self
-    }
-}
-
-impl ResourcePath for bytestring::ByteString {
-    fn path(&self) -> &str {
-        &*self
-    }
-}
-
-/// One or many patterns.
-#[derive(Debug, Clone, PartialEq, Eq, Hash)]
-pub enum Patterns {
-    Single(String),
-    List(Vec<String>),
-}
-
-impl Patterns {
-    pub fn is_empty(&self) -> bool {
-        match self {
-            Patterns::Single(_) => false,
-            Patterns::List(pats) => pats.is_empty(),
-        }
-    }
-}
-
-/// Helper trait for type that could be converted to one or more path pattern.
-pub trait IntoPatterns {
-    fn patterns(&self) -> Patterns;
-}
-
-impl IntoPatterns for String {
-    fn patterns(&self) -> Patterns {
-        Patterns::Single(self.clone())
-    }
-}
-
-impl<'a> IntoPatterns for &'a String {
-    fn patterns(&self) -> Patterns {
-        Patterns::Single((*self).clone())
-    }
-}
-
-impl<'a> IntoPatterns for &'a str {
-    fn patterns(&self) -> Patterns {
-        Patterns::Single((*self).to_owned())
-    }
-}
-
-impl IntoPatterns for bytestring::ByteString {
-    fn patterns(&self) -> Patterns {
-        Patterns::Single(self.to_string())
-    }
-}
-
-impl IntoPatterns for Patterns {
-    fn patterns(&self) -> Patterns {
-        self.clone()
-    }
-}
-
-impl<T: AsRef<str>> IntoPatterns for Vec<T> {
-    fn patterns(&self) -> Patterns {
-        let mut patterns = self.iter().map(|v| v.as_ref().to_owned());
-
-        match patterns.size_hint() {
-            (1, _) => Patterns::Single(patterns.next().unwrap()),
-            _ => Patterns::List(patterns.collect()),
-        }
-    }
-}
-
-macro_rules! array_patterns_single (($tp:ty) => {
-    impl IntoPatterns for [$tp; 1] {
-        fn patterns(&self) -> Patterns {
-            Patterns::Single(self[0].to_owned())
-        }
-    }
-});
-
-macro_rules! array_patterns_multiple (($tp:ty, $str_fn:expr, $($num:tt) +) => {
-    // for each array length specified in $num
-    $(
-        impl IntoPatterns for [$tp; $num] {
-            fn patterns(&self) -> Patterns {
-                Patterns::List(self.iter().map($str_fn).collect())
-            }
-        }
-    )+
-});
-
-array_patterns_single!(&str);
-array_patterns_multiple!(&str, |&v| v.to_owned(), 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16);
-
-array_patterns_single!(String);
-array_patterns_multiple!(String, |v| v.clone(), 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16);
-
 #[cfg(feature = "http")]
 mod url;

+pub use self::de::PathDeserializer;
+pub use self::path::Path;
+pub use self::pattern::{IntoPatterns, Patterns};
+pub use self::resource::ResourceDef;
+pub use self::resource_path::{Resource, ResourcePath};
+pub use self::router::{ResourceInfo, Router, RouterBuilder};
+
 #[cfg(feature = "http")]
 pub use self::url::{Quoter, Url};
-
-#[cfg(feature = "http")]
-mod http_impls {
-    use http::Uri;
-
-    use super::ResourcePath;
-
-    impl ResourcePath for Uri {
-        fn path(&self) -> &str {
-            self.path()
-        }
-    }
-}
--- a/actix-router/src/pattern.rs
+++ b/actix-router/src/pattern.rs
@@ -0,0 +1,92 @@
+/// One or many patterns.
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub enum Patterns {
+    Single(String),
+    List(Vec<String>),
+}
+
+impl Patterns {
+    pub fn is_empty(&self) -> bool {
+        match self {
+            Patterns::Single(_) => false,
+            Patterns::List(pats) => pats.is_empty(),
+        }
+    }
+}
+
+/// Helper trait for type that could be converted to one or more path patterns.
+pub trait IntoPatterns {
+    fn patterns(&self) -> Patterns;
+}
+
+impl IntoPatterns for String {
+    fn patterns(&self) -> Patterns {
+        Patterns::Single(self.clone())
+    }
+}
+
+impl IntoPatterns for &String {
+    fn patterns(&self) -> Patterns {
+        (*self).patterns()
+    }
+}
+
+impl IntoPatterns for str {
+    fn patterns(&self) -> Patterns {
+        Patterns::Single(self.to_owned())
+    }
+}
+
+impl IntoPatterns for &str {
+    fn patterns(&self) -> Patterns {
+        (*self).patterns()
+    }
+}
+
+impl IntoPatterns for bytestring::ByteString {
+    fn patterns(&self) -> Patterns {
+        Patterns::Single(self.to_string())
+    }
+}
+
+impl IntoPatterns for Patterns {
+    fn patterns(&self) -> Patterns {
+        self.clone()
+    }
+}
+
+impl<T: AsRef<str>> IntoPatterns for Vec<T> {
+    fn patterns(&self) -> Patterns {
+        let mut patterns = self.iter().map(|v| v.as_ref().to_owned());
+
+        match patterns.size_hint() {
+            (1, _) => Patterns::Single(patterns.next().unwrap()),
+            _ => Patterns::List(patterns.collect()),
+        }
+    }
+}
+
+macro_rules! array_patterns_single (($tp:ty) => {
+    impl IntoPatterns for [$tp; 1] {
+        fn patterns(&self) -> Patterns {
+            Patterns::Single(self[0].to_owned())
+        }
+    }
+});
+
+macro_rules! array_patterns_multiple (($tp:ty, $str_fn:expr, $($num:tt) +) => {
+    // for each array length specified in space-separated $num
+    $(
+        impl IntoPatterns for [$tp; $num] {
+            fn patterns(&self) -> Patterns {
+                Patterns::List(self.iter().map($str_fn).collect())
+            }
+        }
+    )+
+});
+
+array_patterns_single!(&str);
+array_patterns_multiple!(&str, |&v| v.to_owned(), 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16);
+
+array_patterns_single!(String);
+array_patterns_multiple!(String, |v| v.clone(), 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16);
--- a/actix-router/src/resource_path.rs
+++ b/actix-router/src/resource_path.rs
@@ -0,0 +1,36 @@
+use crate::Path;
+
+// TODO: this trait is necessary, document it
+// see impl Resource for ServiceRequest
+pub trait Resource<T: ResourcePath> {
+    fn resource_path(&mut self) -> &mut Path<T>;
+}
+
+pub trait ResourcePath {
+    fn path(&self) -> &str;
+}
+
+impl ResourcePath for String {
+    fn path(&self) -> &str {
+        self.as_str()
+    }
+}
+
+impl<'a> ResourcePath for &'a str {
+    fn path(&self) -> &str {
+        self
+    }
+}
+
+impl ResourcePath for bytestring::ByteString {
+    fn path(&self) -> &str {
+        &*self
+    }
+}
+
+#[cfg(feature = "http")]
+impl ResourcePath for http::Uri {
+    fn path(&self) -> &str {
+        self.path()
+    }
+}
--- a/actix-test/CHANGES.md
+++ b/actix-test/CHANGES.md
@@ -3,6 +3,10 @@
 ## Unreleased - 2021-xx-xx


+## 0.1.0-beta.8 - 2021-12-11
+* No significant changes since `0.1.0-beta.7`.
+
+
 ## 0.1.0-beta.7 - 2021-11-22
 * Fix compatibility with experimental `io-uring` feature of `actix-rt`. [#2408]

--- a/actix-test/Cargo.toml
+++ b/actix-test/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "actix-test"
-version = "0.1.0-beta.7"
+version = "0.1.0-beta.8"
 authors = [
    "Nikolay Kim <fafhrd91@gmail.com>",
    "Rob Ede <robjtede@icloud.com>",
@@ -29,13 +29,13 @@ openssl = ["tls-openssl", "actix-http/openssl", "awc/openssl"]

 [dependencies]
 actix-codec = "0.4.1"
-actix-http = "3.0.0-beta.14"
-actix-http-test = "3.0.0-beta.7"
+actix-http = "3.0.0-beta.15"
+actix-http-test = "3.0.0-beta.9"
+actix-rt = "2.1"
 actix-service = "2.0.0"
 actix-utils = "3.0.0"
-actix-web = { version = "4.0.0-beta.11", default-features = false, features = ["cookies"] }
-actix-rt = "2.1"
-awc = { version = "3.0.0-beta.11", default-features = false, features = ["cookies"] }
+actix-web = { version = "4.0.0-beta.14", default-features = false, features = ["cookies"] }
+awc = { version = "3.0.0-beta.13", default-features = false, features = ["cookies"] }

 futures-core = { version = "0.3.7", default-features = false, features = ["std"] }
 futures-util = { version = "0.3.7", default-features = false, features = [] }
--- a/actix-test/src/lib.rs
+++ b/actix-test/src/lib.rs
@@ -163,11 +163,9 @@ where
                            local_addr,
                        );

-                        let fac = factory().into_factory().map_err(|err| {
-                            let res: actix_http::Response<_> =
-                                err.into().error_response().into();
-                            res.map_into_boxed_body()
-                        });
+                        let fac = factory()
+                            .into_factory()
+                            .map_err(|err| err.into().error_response());

                        HttpService::build()
                            .client_timeout(timeout)
@@ -181,11 +179,9 @@ where
                            local_addr,
                        );

-                        let fac = factory().into_factory().map_err(|err| {
-                            let res: actix_http::Response<_> =
-                                err.into().error_response().into();
-                            res.map_into_boxed_body()
-                        });
+                        let fac = factory()
+                            .into_factory()
+                            .map_err(|err| err.into().error_response());

                        HttpService::build()
                            .client_timeout(timeout)
@@ -199,11 +195,9 @@ where
                            local_addr,
                        );

-                        let fac = factory().into_factory().map_err(|err| {
-                            let res: actix_http::Response<_> =
-                                err.into().error_response().into();
-                            res.map_into_boxed_body()
-                        });
+                        let fac = factory()
+                            .into_factory()
+                            .map_err(|err| err.into().error_response());

                        HttpService::build()
                            .client_timeout(timeout)
@@ -220,11 +214,9 @@ where
                            local_addr,
                        );

-                        let fac = factory().into_factory().map_err(|err| {
-                            let res: actix_http::Response<_> =
-                                err.into().error_response().into();
-                            res.map_into_boxed_body()
-                        });
+                        let fac = factory()
+                            .into_factory()
+                            .map_err(|err| err.into().error_response());

                        HttpService::build()
                            .client_timeout(timeout)
@@ -238,11 +230,9 @@ where
                            local_addr,
                        );

-                        let fac = factory().into_factory().map_err(|err| {
-                            let res: actix_http::Response<_> =
-                                err.into().error_response().into();
-                            res.map_into_boxed_body()
-                        });
+                        let fac = factory()
+                            .into_factory()
+                            .map_err(|err| err.into().error_response());

                        HttpService::build()
                            .client_timeout(timeout)
@@ -256,11 +246,9 @@ where
                            local_addr,
                        );

-                        let fac = factory().into_factory().map_err(|err| {
-                            let res: actix_http::Response<_> =
-                                err.into().error_response().into();
-                            res.map_into_boxed_body()
-                        });
+                        let fac = factory()
+                            .into_factory()
+                            .map_err(|err| err.into().error_response());

                        HttpService::build()
                            .client_timeout(timeout)
@@ -277,11 +265,9 @@ where
                            local_addr,
                        );

-                        let fac = factory().into_factory().map_err(|err| {
-                            let res: actix_http::Response<_> =
-                                err.into().error_response().into();
-                            res.map_into_boxed_body()
-                        });
+                        let fac = factory()
+                            .into_factory()
+                            .map_err(|err| err.into().error_response());

                        HttpService::build()
                            .client_timeout(timeout)
@@ -295,11 +281,9 @@ where
                            local_addr,
                        );

-                        let fac = factory().into_factory().map_err(|err| {
-                            let res: actix_http::Response<_> =
-                                err.into().error_response().into();
-                            res.map_into_boxed_body()
-                        });
+                        let fac = factory()
+                            .into_factory()
+                            .map_err(|err| err.into().error_response());

                        HttpService::build()
                            .client_timeout(timeout)
@@ -313,11 +297,9 @@ where
                            local_addr,
                        );

-                        let fac = factory().into_factory().map_err(|err| {
-                            let res: actix_http::Response<_> =
-                                err.into().error_response().into();
-                            res.map_into_boxed_body()
-                        });
+                        let fac = factory()
+                            .into_factory()
+                            .map_err(|err| err.into().error_response());

                        HttpService::build()
                            .client_timeout(timeout)
--- a/actix-web-actors/CHANGES.md
+++ b/actix-web-actors/CHANGES.md
@@ -1,6 +1,9 @@
 # Changes

 ## Unreleased - 2021-xx-xx
+
+
+## 4.0.0-beta.8 - 2021-12-11
 * Add `ws:WsResponseBuilder` for building WebSocket session response. [#1920]
 * Deprecate `ws::{start_with_addr, start_with_protocols}`. [#1920]
 * Minimum supported Rust version (MSRV) is now 1.52.
--- a/actix-web-actors/Cargo.toml
+++ b/actix-web-actors/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "actix-web-actors"
-version = "4.0.0-beta.7"
+version = "4.0.0-beta.8"
 authors = ["Nikolay Kim <fafhrd91@gmail.com>"]
 description = "Actix actors support for Actix Web"
 keywords = ["actix", "http", "web", "framework", "async"]
@@ -16,8 +16,8 @@ path = "src/lib.rs"
 [dependencies]
 actix = { version = "0.12.0", default-features = false }
 actix-codec = "0.4.1"
-actix-http = "3.0.0-beta.14"
-actix-web = { version = "4.0.0-beta.11", default-features = false }
+actix-http = "3.0.0-beta.15"
+actix-web = { version = "4.0.0-beta.14", default-features = false }

 bytes = "1"
 bytestring = "1"
@@ -27,8 +27,8 @@ tokio = { version = "1", features = ["sync"] }

 [dev-dependencies]
 actix-rt = "2.2"
-actix-test = "0.1.0-beta.7"
+actix-test = "0.1.0-beta.8"
+awc = { version = "3.0.0-beta.13", default-features = false }

-awc = { version = "3.0.0-beta.11", default-features = false }
 env_logger = "0.9"
 futures-util = { version = "0.3.7", default-features = false }
--- a/actix-web-actors/README.md
+++ b/actix-web-actors/README.md
@@ -3,11 +3,11 @@
 > Actix actors support for Actix Web.

 [![crates.io](https://img.shields.io/crates/v/actix-web-actors?label=latest)](https://crates.io/crates/actix-web-actors)
-[![Documentation](https://docs.rs/actix-web-actors/badge.svg?version=4.0.0-beta.7)](https://docs.rs/actix-web-actors/4.0.0-beta.7)
+[![Documentation](https://docs.rs/actix-web-actors/badge.svg?version=4.0.0-beta.8)](https://docs.rs/actix-web-actors/4.0.0-beta.8)
 [![Version](https://img.shields.io/badge/rustc-1.52+-ab6000.svg)](https://blog.rust-lang.org/2021/05/06/Rust-1.52.0.html)
 ![License](https://img.shields.io/crates/l/actix-web-actors.svg)
 <br />
-[![dependency status](https://deps.rs/crate/actix-web-actors/4.0.0-beta.7/status.svg)](https://deps.rs/crate/actix-web-actors/4.0.0-beta.7)
+[![dependency status](https://deps.rs/crate/actix-web-actors/4.0.0-beta.8/status.svg)](https://deps.rs/crate/actix-web-actors/4.0.0-beta.8)
 [![Download](https://img.shields.io/crates/d/actix-web-actors.svg)](https://crates.io/crates/actix-web-actors)
 [![Chat on Discord](https://img.shields.io/discord/771444961383153695?label=chat&logo=discord)](https://discord.gg/NWpN5mmg3x)

--- a/actix-web-codegen/CHANGES.md
+++ b/actix-web-codegen/CHANGES.md
@@ -3,6 +3,10 @@
 ## Unreleased - 2021-xx-xx


+## 0.5.0-beta.6 - 2021-12-11
+* No significant changes since `0.5.0-beta.5`.
+
+
 ## 0.5.0-beta.5 - 2021-10-20
 * Improve error recovery potential when macro input is invalid. [#2410]
 * Add `#[actix_web::test]` macro for setting up tests with a runtime. [#2409]
--- a/actix-web-codegen/Cargo.toml
+++ b/actix-web-codegen/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "actix-web-codegen"
-version = "0.5.0-beta.5"
+version = "0.5.0-beta.6"
 description = "Routing and runtime macros for Actix Web"
 homepage = "https://actix.rs"
 repository = "https://github.com/actix/actix-web.git"
@@ -21,11 +21,11 @@ proc-macro2 = "1"
 actix-router = "0.5.0-beta.2"

 [dev-dependencies]
-actix-rt = "2.2"
 actix-macros = "0.2.3"
-actix-test = "0.1.0-beta.7"
+actix-rt = "2.2"
+actix-test = "0.1.0-beta.8"
 actix-utils = "3.0.0"
-actix-web = "4.0.0-beta.11"
+actix-web = "4.0.0-beta.14"

 futures-core = { version = "0.3.7", default-features = false, features = ["alloc"] }
 trybuild = "1"
--- a/actix-web-codegen/README.md
+++ b/actix-web-codegen/README.md
@@ -3,11 +3,11 @@
 > Routing and runtime macros for Actix Web.

 [![crates.io](https://img.shields.io/crates/v/actix-web-codegen?label=latest)](https://crates.io/crates/actix-web-codegen)
-[![Documentation](https://docs.rs/actix-web-codegen/badge.svg?version=0.5.0-beta.5)](https://docs.rs/actix-web-codegen/0.5.0-beta.5)
+[![Documentation](https://docs.rs/actix-web-codegen/badge.svg?version=0.5.0-beta.6)](https://docs.rs/actix-web-codegen/0.5.0-beta.6)
 [![Version](https://img.shields.io/badge/rustc-1.52+-ab6000.svg)](https://blog.rust-lang.org/2021/05/06/Rust-1.52.0.html)
 ![License](https://img.shields.io/crates/l/actix-web-codegen.svg)
 <br />
-[![dependency status](https://deps.rs/crate/actix-web-codegen/0.5.0-beta.5/status.svg)](https://deps.rs/crate/actix-web-codegen/0.5.0-beta.5)
+[![dependency status](https://deps.rs/crate/actix-web-codegen/0.5.0-beta.6/status.svg)](https://deps.rs/crate/actix-web-codegen/0.5.0-beta.6)
 [![Download](https://img.shields.io/crates/d/actix-web-codegen.svg)](https://crates.io/crates/actix-web-codegen)
 [![Chat on Discord](https://img.shields.io/discord/771444961383153695?label=chat&logo=discord)](https://discord.gg/NWpN5mmg3x)

--- a/awc/CHANGES.md
+++ b/awc/CHANGES.md
@@ -1,6 +1,13 @@
 # Changes

 ## Unreleased - 2021-xx-xx
+* Add `ClientBuilder::add_default_header` and deprecate `ClientBuilder::header`. [#2510]
+
+[#2510]: https://github.com/actix/actix-web/pull/2510
+
+
+## 3.0.0-beta.13 - 2021-12-11
+* No significant changes since `3.0.0-beta.12`.


 ## 3.0.0-beta.12 - 2021-11-30
@@ -56,7 +63,7 @@
 * `ConnectorService` type is renamed to `BoxConnectorService`. [#2081]
 * Fix http/https encoding when enabling `compress` feature. [#2116]
 * Rename `TestResponse::header` to `append_header`, `set` to `insert_header`. `TestResponse` header
-  methods now take `IntoHeaderPair` tuples. [#2094]
+  methods now take `TryIntoHeaderPair` tuples. [#2094]

 [#2081]: https://github.com/actix/actix-web/pull/2081
 [#2094]: https://github.com/actix/actix-web/pull/2094
--- a/awc/Cargo.toml
+++ b/awc/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "awc"
-version = "3.0.0-beta.12"
+version = "3.0.0-beta.13"
 authors = [
    "Nikolay Kim <fafhrd91@gmail.com>",
    "fakeshadow <24548779@qq.com>",
@@ -60,7 +60,7 @@ dangerous-h2c = []
 [dependencies]
 actix-codec = "0.4.1"
 actix-service = "2.0.0"
-actix-http = "3.0.0-beta.14"
+actix-http = "3.0.0-beta.15"
 actix-rt = { version = "2.1", default-features = false }
 actix-tls = { version = "3.0.0-rc.1", features = ["connect", "uri"] }
 actix-utils = "3.0.0"
@@ -72,7 +72,7 @@ cfg-if = "1"
 derive_more = "0.99.5"
 futures-core = { version = "0.3.7", default-features = false }
 futures-util = { version = "0.3.7", default-features = false }
-h2 = "0.3"
+h2 = "0.3.9"
 http = "0.2.5"
 itoa = "0.4"
 log =" 0.4"
@@ -93,13 +93,13 @@ tls-rustls = { package = "rustls", version = "0.20.0", optional = true, features
 trust-dns-resolver = { version = "0.20.0", optional = true }

 [dev-dependencies]
-actix-web = { version = "4.0.0-beta.11", features = ["openssl"] }
-actix-http = { version = "3.0.0-beta.14", features = ["openssl"] }
-actix-http-test = { version = "3.0.0-beta.7", features = ["openssl"] }
-actix-utils = "3.0.0"
+actix-http = { version = "3.0.0-beta.15", features = ["openssl"] }
+actix-http-test = { version = "3.0.0-beta.9", features = ["openssl"] }
 actix-server = "2.0.0-rc.1"
+actix-test = { version = "0.1.0-beta.8", features = ["openssl", "rustls"] }
 actix-tls = { version = "3.0.0-rc.1", features = ["openssl", "rustls"] }
-actix-test = { version = "0.1.0-beta.7", features = ["openssl", "rustls"] }
+actix-utils = "3.0.0"
+actix-web = { version = "4.0.0-beta.14", features = ["openssl"] }

 brotli2 = "0.3.2"
 env_logger = "0.9"
--- a/awc/README.md
+++ b/awc/README.md
@@ -3,9 +3,9 @@
 > Async HTTP and WebSocket client library.

 [![crates.io](https://img.shields.io/crates/v/awc?label=latest)](https://crates.io/crates/awc)
-[![Documentation](https://docs.rs/awc/badge.svg?version=3.0.0-beta.12)](https://docs.rs/awc/3.0.0-beta.12)
+[![Documentation](https://docs.rs/awc/badge.svg?version=3.0.0-beta.13)](https://docs.rs/awc/3.0.0-beta.13)
 ![MIT or Apache 2.0 licensed](https://img.shields.io/crates/l/awc)
-[![Dependency Status](https://deps.rs/crate/awc/3.0.0-beta.12/status.svg)](https://deps.rs/crate/awc/3.0.0-beta.12)
+[![Dependency Status](https://deps.rs/crate/awc/3.0.0-beta.13/status.svg)](https://deps.rs/crate/awc/3.0.0-beta.13)
 [![Chat on Discord](https://img.shields.io/discord/771444961383153695?label=chat&logo=discord)](https://discord.gg/NWpN5mmg3x)

 ## Documentation & Resources
--- a/awc/src/builder.rs
+++ b/awc/src/builder.rs
@@ -2,7 +2,7 @@ use std::{convert::TryFrom, fmt, net::IpAddr, rc::Rc, time::Duration};

 use actix_http::{
    error::HttpError,
-    header::{self, HeaderMap, HeaderName},
+    header::{self, HeaderMap, HeaderName, TryIntoHeaderPair},
    Uri,
 };
 use actix_rt::net::{ActixStream, TcpStream};
@@ -21,11 +21,11 @@ use crate::{
 /// This type can be used to construct an instance of `Client` through a
 /// builder-like pattern.
 pub struct ClientBuilder<S = (), M = ()> {
-    default_headers: bool,
    max_http_version: Option<http::Version>,
    stream_window_size: Option<u32>,
    conn_window_size: Option<u32>,
-    headers: HeaderMap,
+    fundamental_headers: bool,
+    default_headers: HeaderMap,
    timeout: Option<Duration>,
    connector: Connector<S>,
    middleware: M,
@@ -44,15 +44,15 @@ impl ClientBuilder {
        (),
    > {
        ClientBuilder {
-            middleware: (),
-            default_headers: true,
-            headers: HeaderMap::new(),
-            timeout: Some(Duration::from_secs(5)),
-            local_address: None,
-            connector: Connector::new(),
            max_http_version: None,
            stream_window_size: None,
            conn_window_size: None,
+            fundamental_headers: true,
+            default_headers: HeaderMap::new(),
+            timeout: Some(Duration::from_secs(5)),
+            connector: Connector::new(),
+            middleware: (),
+            local_address: None,
            max_redirects: 10,
        }
    }
@@ -78,8 +78,8 @@ where
    {
        ClientBuilder {
            middleware: self.middleware,
+            fundamental_headers: self.fundamental_headers,
            default_headers: self.default_headers,
-            headers: self.headers,
            timeout: self.timeout,
            local_address: self.local_address,
            connector,
@@ -153,30 +153,46 @@ where
        self
    }

-    /// Do not add default request headers.
+    /// Do not add fundamental default request headers.
+    ///
    /// By default `Date` and `User-Agent` headers are set.
    pub fn no_default_headers(mut self) -> Self {
-        self.default_headers = false;
+        self.fundamental_headers = false;
        self
    }

-    /// Add default header. Headers added by this method
-    /// get added to every request.
+    /// Add default header.
+    ///
+    /// Headers added by this method get added to every request unless overriden by .
+    ///
+    /// # Panics
+    /// Panics if header name or value is invalid.
+    pub fn add_default_header(mut self, header: impl TryIntoHeaderPair) -> Self {
+        match header.try_into_pair() {
+            Ok((key, value)) => self.default_headers.append(key, value),
+            Err(err) => panic!("Header error: {:?}", err.into()),
+        }
+
+        self
+    }
+
+    #[doc(hidden)]
+    #[deprecated(since = "3.0.0", note = "Prefer `add_default_header((key, value))`.")]
    pub fn header<K, V>(mut self, key: K, value: V) -> Self
    where
        HeaderName: TryFrom<K>,
        <HeaderName as TryFrom<K>>::Error: fmt::Debug + Into<HttpError>,
-        V: header::IntoHeaderValue,
+        V: header::TryIntoHeaderValue,
        V::Error: fmt::Debug,
    {
        match HeaderName::try_from(key) {
            Ok(key) => match value.try_into_value() {
                Ok(value) => {
-                    self.headers.append(key, value);
+                    self.default_headers.append(key, value);
                }
-                Err(e) => log::error!("Header value error: {:?}", e),
+                Err(err) => log::error!("Header value error: {:?}", err),
            },
-            Err(e) => log::error!("Header name error: {:?}", e),
+            Err(err) => log::error!("Header name error: {:?}", err),
        }
        self
    }
@@ -190,10 +206,10 @@ where
            Some(password) => format!("{}:{}", username, password),
            None => format!("{}:", username),
        };
-        self.header(
+        self.add_default_header((
            header::AUTHORIZATION,
            format!("Basic {}", base64::encode(&auth)),
-        )
+        ))
    }

    /// Set client wide HTTP bearer authentication header
@@ -201,13 +217,12 @@ where
    where
        T: fmt::Display,
    {
-        self.header(header::AUTHORIZATION, format!("Bearer {}", token))
+        self.add_default_header((header::AUTHORIZATION, format!("Bearer {}", token)))
    }

-    /// Registers middleware, in the form of a middleware component (type),
-    /// that runs during inbound and/or outbound processing in the request
-    /// life-cycle (request -> response), modifying request/response as
-    /// necessary, across all requests managed by the Client.
+    /// Registers middleware, in the form of a middleware component (type), that runs during inbound
+    /// and/or outbound processing in the request life-cycle (request -> response),
+    /// modifying request/response as necessary, across all requests managed by the `Client`.
    pub fn wrap<S1, M1>(
        self,
        mw: M1,
@@ -218,11 +233,11 @@ where
    {
        ClientBuilder {
            middleware: NestTransform::new(self.middleware, mw),
-            default_headers: self.default_headers,
+            fundamental_headers: self.fundamental_headers,
            max_http_version: self.max_http_version,
            stream_window_size: self.stream_window_size,
            conn_window_size: self.conn_window_size,
-            headers: self.headers,
+            default_headers: self.default_headers,
            timeout: self.timeout,
            connector: self.connector,
            local_address: self.local_address,
@@ -237,10 +252,10 @@ where
        M::Transform:
            Service<ConnectRequest, Response = ConnectResponse, Error = SendRequestError>,
    {
-        let redirect_time = self.max_redirects;
+        let max_redirects = self.max_redirects;

-        if redirect_time > 0 {
-            self.wrap(Redirect::new().max_redirect_times(redirect_time))
+        if max_redirects > 0 {
+            self.wrap(Redirect::new().max_redirect_times(max_redirects))
                ._finish()
        } else {
            self._finish()
@@ -272,7 +287,7 @@ where
        let connector = boxed::rc_service(self.middleware.new_transform(connector));

        Client(ClientConfig {
-            headers: Rc::new(self.headers),
+            default_headers: Rc::new(self.default_headers),
            timeout: self.timeout,
            connector,
        })
@@ -288,7 +303,7 @@ mod tests {
        let client = ClientBuilder::new().basic_auth("username", Some("password"));
        assert_eq!(
            client
-                .headers
+                .default_headers
                .get(header::AUTHORIZATION)
                .unwrap()
                .to_str()
@@ -299,7 +314,7 @@ mod tests {
        let client = ClientBuilder::new().basic_auth("username", None);
        assert_eq!(
            client
-                .headers
+                .default_headers
                .get(header::AUTHORIZATION)
                .unwrap()
                .to_str()
@@ -313,7 +328,7 @@ mod tests {
        let client = ClientBuilder::new().bearer_auth("someS3cr3tAutht0k3n");
        assert_eq!(
            client
-                .headers
+                .default_headers
                .get(header::AUTHORIZATION)
                .unwrap()
                .to_str()
--- a/awc/src/client/h1proto.rs
+++ b/awc/src/client/h1proto.rs
@@ -9,7 +9,7 @@ use actix_http::{
    body::{BodySize, MessageBody},
    error::PayloadError,
    h1,
-    header::{HeaderMap, IntoHeaderValue, EXPECT, HOST},
+    header::{HeaderMap, TryIntoHeaderValue, EXPECT, HOST},
    Payload, RequestHeadType, ResponseHead, StatusCode,
 };
 use actix_utils::future::poll_fn;
--- a/awc/src/frozen.rs
+++ b/awc/src/frozen.rs
@@ -6,7 +6,7 @@ use serde::Serialize;

 use actix_http::{
    error::HttpError,
-    header::{HeaderMap, HeaderName, IntoHeaderValue},
+    header::{HeaderMap, HeaderName, TryIntoHeaderValue},
    Method, RequestHead, Uri,
 };

@@ -114,7 +114,7 @@ impl FrozenClientRequest {
    where
        HeaderName: TryFrom<K>,
        <HeaderName as TryFrom<K>>::Error: Into<HttpError>,
-        V: IntoHeaderValue,
+        V: TryIntoHeaderValue,
    {
        self.extra_headers(HeaderMap::new())
            .extra_header(key, value)
@@ -142,7 +142,7 @@ impl FrozenSendBuilder {
    where
        HeaderName: TryFrom<K>,
        <HeaderName as TryFrom<K>>::Error: Into<HttpError>,
-        V: IntoHeaderValue,
+        V: TryIntoHeaderValue,
    {
        match HeaderName::try_from(key) {
            Ok(key) => match value.try_into_value() {
--- a/awc/src/lib.rs
+++ b/awc/src/lib.rs
@@ -168,7 +168,7 @@ pub struct Client(ClientConfig);
 #[derive(Clone)]
 pub(crate) struct ClientConfig {
    pub(crate) connector: BoxConnectorService,
-    pub(crate) headers: Rc<HeaderMap>,
+    pub(crate) default_headers: Rc<HeaderMap>,
    pub(crate) timeout: Option<Duration>,
 }

@@ -204,7 +204,9 @@ impl Client {
    {
        let mut req = ClientRequest::new(method, url, self.0.clone());

-        for header in self.0.headers.iter() {
+        for header in self.0.default_headers.iter() {
+            // header map is empty
+            // TODO: probably append instead
            req = req.insert_header_if_none(header);
        }
        req
@@ -297,7 +299,7 @@ impl Client {
        <Uri as TryFrom<U>>::Error: Into<HttpError>,
    {
        let mut req = ws::WebsocketsRequest::new(url, self.0.clone());
-        for (key, value) in self.0.headers.iter() {
+        for (key, value) in self.0.default_headers.iter() {
            req.head.headers.insert(key.clone(), value.clone());
        }
        req
@@ -308,6 +310,6 @@ impl Client {
    /// Returns Some(&mut HeaderMap) when Client object is unique
    /// (No other clone of client exists at the same time).
    pub fn headers(&mut self) -> Option<&mut HeaderMap> {
-        Rc::get_mut(&mut self.0.headers)
+        Rc::get_mut(&mut self.0.default_headers)
    }
 }
--- a/awc/src/middleware/redirect.rs
+++ b/awc/src/middleware/redirect.rs
@@ -442,13 +442,15 @@ mod tests {
        });

        let client = ClientBuilder::new()
-            .header("custom", "value")
+            .add_default_header(("custom", "value"))
            .disable_redirects()
            .finish();
        let res = client.get(srv.url("/")).send().await.unwrap();
        assert_eq!(res.status().as_u16(), 302);

-        let client = ClientBuilder::new().header("custom", "value").finish();
+        let client = ClientBuilder::new()
+            .add_default_header(("custom", "value"))
+            .finish();
        let res = client.get(srv.url("/")).send().await.unwrap();
        assert_eq!(res.status().as_u16(), 200);

@@ -520,7 +522,7 @@ mod tests {

        // send a request to different origins, http://srv1/ then http://srv2/. So it should remove the header
        let client = ClientBuilder::new()
-            .header(header::AUTHORIZATION, "auth_key_value")
+            .add_default_header((header::AUTHORIZATION, "auth_key_value"))
            .finish();
        let res = client.get(srv1.url("/")).send().await.unwrap();
        assert_eq!(res.status().as_u16(), 200);
--- a/awc/src/request.rs
+++ b/awc/src/request.rs
@@ -6,7 +6,7 @@ use serde::Serialize;

 use actix_http::{
    error::HttpError,
-    header::{self, HeaderMap, HeaderValue, IntoHeaderPair},
+    header::{self, HeaderMap, HeaderValue, TryIntoHeaderPair},
    ConnectionType, Method, RequestHead, Uri, Version,
 };

@@ -147,11 +147,8 @@ impl ClientRequest {
    }

    /// Insert a header, replacing any that were set with an equivalent field name.
-    pub fn insert_header<H>(mut self, header: H) -> Self
-    where
-        H: IntoHeaderPair,
-    {
-        match header.try_into_header_pair() {
+    pub fn insert_header(mut self, header: impl TryIntoHeaderPair) -> Self {
+        match header.try_into_pair() {
            Ok((key, value)) => {
                self.head.headers.insert(key, value);
            }
@@ -162,11 +159,8 @@ impl ClientRequest {
    }

    /// Insert a header only if it is not yet set.
-    pub fn insert_header_if_none<H>(mut self, header: H) -> Self
-    where
-        H: IntoHeaderPair,
-    {
-        match header.try_into_header_pair() {
+    pub fn insert_header_if_none(mut self, header: impl TryIntoHeaderPair) -> Self {
+        match header.try_into_pair() {
            Ok((key, value)) => {
                if !self.head.headers.contains_key(&key) {
                    self.head.headers.insert(key, value);
@@ -192,11 +186,8 @@ impl ClientRequest {
    ///     .insert_header((CONTENT_TYPE, mime::APPLICATION_JSON));
    /// # }
    /// ```
-    pub fn append_header<H>(mut self, header: H) -> Self
-    where
-        H: IntoHeaderPair,
-    {
-        match header.try_into_header_pair() {
+    pub fn append_header(mut self, header: impl TryIntoHeaderPair) -> Self {
+        match header.try_into_pair() {
            Ok((key, value)) => self.head.headers.append(key, value),
            Err(e) => self.err = Some(e.into()),
        };
@@ -588,7 +579,7 @@ mod tests {
    #[actix_rt::test]
    async fn test_client_header() {
        let req = Client::builder()
-            .header(header::CONTENT_TYPE, "111")
+            .add_default_header((header::CONTENT_TYPE, "111"))
            .finish()
            .get("/");

@@ -606,7 +597,7 @@ mod tests {
    #[actix_rt::test]
    async fn test_client_header_override() {
        let req = Client::builder()
-            .header(header::CONTENT_TYPE, "111")
+            .add_default_header((header::CONTENT_TYPE, "111"))
            .finish()
            .get("/")
            .insert_header((header::CONTENT_TYPE, "222"));
--- a/awc/src/sender.rs
+++ b/awc/src/sender.rs
@@ -10,7 +10,7 @@ use std::{
 use actix_http::{
    body::BodyStream,
    error::HttpError,
-    header::{self, HeaderMap, HeaderName, IntoHeaderValue},
+    header::{self, HeaderMap, HeaderName, TryIntoHeaderValue},
    RequestHead, RequestHeadType,
 };
 use actix_rt::time::{sleep, Sleep};
@@ -298,7 +298,7 @@ impl RequestSender {

    fn set_header_if_none<V>(&mut self, key: HeaderName, value: V) -> Result<(), HttpError>
    where
-        V: IntoHeaderValue,
+        V: TryIntoHeaderValue,
    {
        match self {
            RequestSender::Owned(head) => {
--- a/awc/src/test.rs
+++ b/awc/src/test.rs
@@ -1,6 +1,6 @@
 //! Test helpers for actix http client to use during testing.

-use actix_http::{h1, header::IntoHeaderPair, Payload, ResponseHead, StatusCode, Version};
+use actix_http::{h1, header::TryIntoHeaderPair, Payload, ResponseHead, StatusCode, Version};
 use bytes::Bytes;

 #[cfg(feature = "cookies")]
@@ -28,10 +28,7 @@ impl Default for TestResponse {

 impl TestResponse {
    /// Create TestResponse and set header
-    pub fn with_header<H>(header: H) -> Self
-    where
-        H: IntoHeaderPair,
-    {
+    pub fn with_header(header: impl TryIntoHeaderPair) -> Self {
        Self::default().insert_header(header)
    }

@@ -42,11 +39,8 @@ impl TestResponse {
    }

    /// Insert a header
-    pub fn insert_header<H>(mut self, header: H) -> Self
-    where
-        H: IntoHeaderPair,
-    {
-        if let Ok((key, value)) = header.try_into_header_pair() {
+    pub fn insert_header(mut self, header: impl TryIntoHeaderPair) -> Self {
+        if let Ok((key, value)) = header.try_into_pair() {
            self.head.headers.insert(key, value);
            return self;
        }
@@ -54,11 +48,8 @@ impl TestResponse {
    }

    /// Append a header
-    pub fn append_header<H>(mut self, header: H) -> Self
-    where
-        H: IntoHeaderPair,
-    {
-        if let Ok((key, value)) = header.try_into_header_pair() {
+    pub fn append_header(mut self, header: impl TryIntoHeaderPair) -> Self {
+        if let Ok((key, value)) = header.try_into_pair() {
            self.head.headers.append(key, value);
            return self;
        }
--- a/awc/src/ws.rs
+++ b/awc/src/ws.rs
@@ -39,7 +39,7 @@ use crate::{
    connect::{BoxedSocket, ConnectRequest},
    error::{HttpError, InvalidUrl, SendRequestError, WsClientError},
    http::{
-        header::{self, HeaderName, HeaderValue, IntoHeaderValue, AUTHORIZATION},
+        header::{self, HeaderName, HeaderValue, TryIntoHeaderValue, AUTHORIZATION},
        ConnectionType, Method, StatusCode, Uri, Version,
    },
    response::ClientResponse,
@@ -171,7 +171,7 @@ impl WebsocketsRequest {
    where
        HeaderName: TryFrom<K>,
        <HeaderName as TryFrom<K>>::Error: Into<HttpError>,
-        V: IntoHeaderValue,
+        V: TryIntoHeaderValue,
    {
        match HeaderName::try_from(key) {
            Ok(key) => match value.try_into_value() {
@@ -190,7 +190,7 @@ impl WebsocketsRequest {
    where
        HeaderName: TryFrom<K>,
        <HeaderName as TryFrom<K>>::Error: Into<HttpError>,
-        V: IntoHeaderValue,
+        V: TryIntoHeaderValue,
    {
        match HeaderName::try_from(key) {
            Ok(key) => match value.try_into_value() {
@@ -209,7 +209,7 @@ impl WebsocketsRequest {
    where
        HeaderName: TryFrom<K>,
        <HeaderName as TryFrom<K>>::Error: Into<HttpError>,
-        V: IntoHeaderValue,
+        V: TryIntoHeaderValue,
    {
        match HeaderName::try_from(key) {
            Ok(key) => {
@@ -445,7 +445,7 @@ mod tests {
    #[actix_rt::test]
    async fn test_header_override() {
        let req = Client::builder()
-            .header(header::CONTENT_TYPE, "111")
+            .add_default_header((header::CONTENT_TYPE, "111"))
            .finish()
            .ws("/")
            .set_header(header::CONTENT_TYPE, "222");
--- a/examples/basic.rs
+++ b/examples/basic.rs
@@ -22,14 +22,14 @@ async fn main() -> std::io::Result<()> {

    HttpServer::new(|| {
        App::new()
-            .wrap(middleware::DefaultHeaders::new().header("X-Version", "0.2"))
+            .wrap(middleware::DefaultHeaders::new().add(("X-Version", "0.2")))
            .wrap(middleware::Compress::default())
            .wrap(middleware::Logger::default())
            .service(index)
            .service(no_params)
            .service(
                web::resource("/resource2/index.html")
-                    .wrap(middleware::DefaultHeaders::new().header("X-Version-R2", "0.3"))
+                    .wrap(middleware::DefaultHeaders::new().add(("X-Version-R2", "0.3")))
                    .default_service(web::route().to(HttpResponse::MethodNotAllowed))
                    .route(web::get().to(index_async)),
            )
--- a/examples/uds.rs
+++ b/examples/uds.rs
@@ -26,14 +26,14 @@ async fn main() -> std::io::Result<()> {

    HttpServer::new(|| {
        App::new()
-            .wrap(middleware::DefaultHeaders::new().header("X-Version", "0.2"))
+            .wrap(middleware::DefaultHeaders::new().add(("X-Version", "0.2")))
            .wrap(middleware::Compress::default())
            .wrap(middleware::Logger::default())
            .service(index)
            .service(no_params)
            .service(
                web::resource("/resource2/index.html")
-                    .wrap(middleware::DefaultHeaders::new().header("X-Version-R2", "0.3"))
+                    .wrap(middleware::DefaultHeaders::new().add(("X-Version-R2", "0.3")))
                    .default_service(web::route().to(HttpResponse::MethodNotAllowed))
                    .route(web::get().to(index_async)),
            )
--- a/scripts/bump
+++ b/scripts/bump
@@ -41,6 +41,8 @@ cat "$CHANGELOG_FILE" |
 # if word count of changelog chunk is 0 then insert filler changelog chunk
 if [ "$(wc -w "$CHANGE_CHUNK_FILE" | awk '{ print $1 }')" = "0" ]; then
    echo "* No significant changes since \`$CURRENT_VERSION\`." >"$CHANGE_CHUNK_FILE"
+    echo >>"$CHANGE_CHUNK_FILE"
+    echo >>"$CHANGE_CHUNK_FILE"
 fi

 if [ -n "${2-}" ]; then
@@ -82,8 +84,33 @@ rm -f $README_FILE.bak
 echo "manifest, changelog, and readme updated"
 echo
 echo "check other references:"
-rg "$PACKAGE_NAME =" || true
-rg "package = \"$PACKAGE_NAME\"" || true
+rg --glob='**/Cargo.toml' "\
+${PACKAGE_NAME} ?= ?\"[^\"]+\"\
+|${PACKAGE_NAME} ?=.*version ?= ?\"([^\"]+)\"\
+|package ?= ?\"${PACKAGE_NAME}\".*version ?= ?\"([^\"]+)\"\
+|version ?= ?\"([^\"]+)\".*package ?= ?\"${PACKAGE_NAME}\"" || true
+
+echo
+read -p "Update all references: (y/N) " UPDATE_REFERENCES
+UPDATE_REFERENCES="${UPDATE_REFERENCES:-n}"
+
+if [ "$UPDATE_REFERENCES" = 'y' ] || [ "$UPDATE_REFERENCES" = 'Y' ]; then
+
+    for f in $(fd Cargo.toml); do
+        sed -i.bak -E \
+            "s/^(${PACKAGE_NAME} ?= ?\")[^\"]+(\")$/\1${NEW_VERSION}\2/g" $f
+        sed -i.bak -E \
+            "s/^(${PACKAGE_NAME} ?=.*version ?= ?\")[^\"]+(\".*)$/\1${NEW_VERSION}\2/g" $f
+        sed -i.bak -E \
+            "s/^(.*package ?= ?\"${PACKAGE_NAME}\".*version ?= ?\")[^\"]+(\".*)$/\1${NEW_VERSION}\2/g" $f
+        sed -i.bak -E \
+            "s/^(.*version ?= ?\")[^\"]+(\".*package ?= ?\"${PACKAGE_NAME}\".*)$/\1${NEW_VERSION}\2/g" $f
+
+        # remove backup file
+        rm -f $f.bak
+    done
+
+fi

 if [ $MACOS ]; then
    printf "prepare $PACKAGE_NAME release $NEW_VERSION" | pbcopy
--- a/src/any_body.rs
+++ b/src/any_body.rs
@@ -1,146 +0,0 @@
-use std::{
-    error::Error as StdError,
-    mem,
-    pin::Pin,
-    task::{Context, Poll},
-};
-
-use actix_http::body::{BodySize, BoxBody, MessageBody};
-use bytes::Bytes;
-use pin_project_lite::pin_project;
-
-use crate::Error;
-
-pin_project! {
-    #[derive(Debug)]
-    #[project = AnyBodyProj]
-    pub enum AnyBody<B = BoxBody> {
-        None,
-        Full { body: Bytes },
-        Stream { #[pin] body: B },
-        Boxed { body: BoxBody },
-    }
-}
-
-impl<B: MessageBody + 'static> AnyBody<B> {
-    pub fn into_body<B1>(self) -> AnyBody<B1> {
-        match self {
-            AnyBody::None => AnyBody::None,
-            AnyBody::Full { body } => AnyBody::Full { body },
-            AnyBody::Stream { body } => AnyBody::Boxed {
-                body: BoxBody::new(body),
-            },
-            AnyBody::Boxed { body } => AnyBody::Boxed { body },
-        }
-    }
-}
-
-impl<B> Default for AnyBody<B> {
-    fn default() -> Self {
-        Self::Full { body: Bytes::new() }
-    }
-}
-
-impl<B> MessageBody for AnyBody<B>
-where
-    B: MessageBody,
-    B::Error: 'static,
-{
-    type Error = Box<dyn StdError>;
-
-    fn size(&self) -> BodySize {
-        match self {
-            Self::None => BodySize::None,
-            Self::Full { body } => body.size(),
-            Self::Stream { body } => body.size(),
-            Self::Boxed { body } => body.size(),
-        }
-    }
-
-    fn poll_next(
-        self: Pin<&mut Self>,
-        cx: &mut Context<'_>,
-    ) -> Poll<Option<Result<Bytes, Self::Error>>> {
-        match self.project() {
-            AnyBodyProj::None => Poll::Ready(None),
-            AnyBodyProj::Full { body } => {
-                let bytes = mem::take(body);
-                Poll::Ready(Some(Ok(bytes)))
-            }
-            AnyBodyProj::Stream { body } => body.poll_next(cx).map_err(|err| err.into()),
-            AnyBodyProj::Boxed { body } => body.as_pin_mut().poll_next(cx),
-        }
-    }
-}
-
-pin_project! {
-    #[project = EitherAnyBodyProj]
-    #[derive(Debug)]
-    pub enum EitherAnyBody<L, R = BoxBody> {
-        /// A body of type `L`.
-        Left { #[pin] body: AnyBody<L> },
-
-        /// A body of type `R`.
-        Right { #[pin] body: AnyBody<R> },
-    }
-}
-
-// impl<L> EitherAnyBody<L, BoxBody> {
-//     /// Creates new `EitherBody` using left variant and boxed right variant.
-//     pub fn new(body: L) -> Self {
-//         Self::Left {
-//             body: AnyBody::Stream { body },
-//         }
-//     }
-// }
-
-// impl<L, R> EitherAnyBody<L, R> {
-//     /// Creates new `EitherBody` using left variant.
-//     pub fn left(body: L) -> Self {
-//         Self::Left {
-//             body: AnyBody::Stream { body },
-//         }
-//     }
-
-//     /// Creates new `EitherBody` using right variant.
-//     pub fn right(body: R) -> Self {
-//         Self::Right {
-//             body: AnyBody::Stream { body },
-//         }
-//     }
-// }
-
-impl<L, R> MessageBody for EitherAnyBody<L, R>
-where
-    L: MessageBody + 'static,
-    R: MessageBody + 'static,
-{
-    type Error = Error;
-
-    fn size(&self) -> BodySize {
-        match self {
-            Self::Left { body } => body.size(),
-            Self::Right { body } => body.size(),
-        }
-    }
-
-    fn poll_next(
-        self: Pin<&mut Self>,
-        cx: &mut Context<'_>,
-    ) -> Poll<Option<Result<Bytes, Self::Error>>> {
-        match self.project() {
-            EitherAnyBodyProj::Left { body } => body.poll_next(cx).map_err(Error::from),
-            EitherAnyBodyProj::Right { body } => body.poll_next(cx).map_err(Error::from),
-        }
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use static_assertions::assert_eq_size;
-
-    use super::*;
-
-    assert_eq_size!(AnyBody<()>, [u8; 40]);
-    assert_eq_size!(AnyBody<u64>, [u8; 40]); // how is this the same size as ()
-}
--- a/src/app.rs
+++ b/src/app.rs
@@ -602,7 +602,7 @@ mod tests {
            App::new()
                .wrap(
                    DefaultHeaders::new()
-                        .header(header::CONTENT_TYPE, HeaderValue::from_static("0001")),
+                        .add((header::CONTENT_TYPE, HeaderValue::from_static("0001"))),
                )
                .route("/test", web::get().to(HttpResponse::Ok)),
        )
@@ -623,7 +623,7 @@ mod tests {
                .route("/test", web::get().to(HttpResponse::Ok))
                .wrap(
                    DefaultHeaders::new()
-                        .header(header::CONTENT_TYPE, HeaderValue::from_static("0001")),
+                        .add((header::CONTENT_TYPE, HeaderValue::from_static("0001"))),
                ),
        )
        .await;
@@ -706,4 +706,25 @@ mod tests {
        let body = read_body(resp).await;
        assert_eq!(body, Bytes::from_static(b"https://youtube.com/watch/12345"));
    }
+
+    /// compile-only test for returning app type from function
+    pub fn foreign_app_type() -> App<
+        impl ServiceFactory<
+            ServiceRequest,
+            Response = ServiceResponse<impl MessageBody>,
+            Config = (),
+            InitError = (),
+            Error = Error,
+        >,
+    > {
+        App::new()
+            // logger can be removed without affecting the return type
+            .wrap(crate::middleware::Logger::default())
+            .route("/", web::to(|| async { "hello" }))
+    }
+
+    #[test]
+    fn return_foreign_app_type() {
+        let _app = foreign_app_type();
+    }
 }
--- a/src/app_service.rs
+++ b/src/app_service.rs
@@ -22,6 +22,7 @@ use crate::{
 type Guards = Vec<Box<dyn Guard>>;

 /// Service factory to convert `Request` to a `ServiceRequest<S>`.
+///
 /// It also executes data factories.
 pub struct AppInit<T, B>
 where
--- a/src/dev.rs
+++ b/src/dev.rs
@@ -102,3 +102,41 @@ impl<B> BodyEncoding for crate::HttpResponse<B> {
        self
    }
 }
+
+// TODO: remove this if it doesn't appear to be needed
+
+#[allow(dead_code)]
+#[derive(Debug)]
+pub(crate) enum AnyBody {
+    None,
+    Full { body: crate::web::Bytes },
+    Boxed { body: actix_http::body::BoxBody },
+}
+
+impl crate::body::MessageBody for AnyBody {
+    type Error = crate::BoxError;
+
+    /// Body size hint.
+    fn size(&self) -> crate::body::BodySize {
+        match self {
+            AnyBody::None => crate::body::BodySize::None,
+            AnyBody::Full { body } => body.size(),
+            AnyBody::Boxed { body } => body.size(),
+        }
+    }
+
+    /// Attempt to pull out the next chunk of body bytes.
+    fn poll_next(
+        self: std::pin::Pin<&mut Self>,
+        cx: &mut std::task::Context<'_>,
+    ) -> std::task::Poll<Option<Result<crate::web::Bytes, Self::Error>>> {
+        match self.get_mut() {
+            AnyBody::None => std::task::Poll::Ready(None),
+            AnyBody::Full { body } => {
+                let bytes = std::mem::take(body);
+                std::task::Poll::Ready(Some(Ok(bytes)))
+            }
+            AnyBody::Boxed { body } => body.as_pin_mut().poll_next(cx),
+        }
+    }
+}
--- a/src/error/error.rs
+++ b/src/error/error.rs
@@ -2,7 +2,7 @@ use std::{error::Error as StdError, fmt};

 use actix_http::{body::BoxBody, Response};

-use crate::{any_body::AnyBody, HttpResponse, ResponseError};
+use crate::{HttpResponse, ResponseError};

 /// General purpose actix web error.
 ///
@@ -69,15 +69,8 @@ impl<T: ResponseError + 'static> From<T> for Error {
    }
 }

-impl From<Error> for Response<AnyBody<BoxBody>> {
-    fn from(err: Error) -> Self {
+impl From<Error> for Response<BoxBody> {
+    fn from(err: Error) -> Response<BoxBody> {
        err.error_response().into()
    }
 }
-
-impl From<Error> for actix_http::Response<BoxBody> {
-    fn from(err: Error) -> Self {
-        let res: actix_http::Response<_> = err.error_response().into();
-        res.map_into_boxed_body()
-    }
-}
--- a/src/error/internal.rs
+++ b/src/error/internal.rs
@@ -2,12 +2,12 @@ use std::{cell::RefCell, fmt, io::Write as _};

 use actix_http::{
    body::BoxBody,
-    header::{self, IntoHeaderValue as _},
+    header::{self, TryIntoHeaderValue as _},
    StatusCode,
 };
 use bytes::{BufMut as _, BytesMut};

-use crate::{any_body::AnyBody, Error, HttpRequest, HttpResponse, Responder, ResponseError};
+use crate::{Error, HttpRequest, HttpResponse, Responder, ResponseError};

 /// Wraps errors to alter the generated response status code.
 ///
@@ -91,9 +91,7 @@ where
                let mime = mime::TEXT_PLAIN_UTF_8.try_into_value().unwrap();
                res.headers_mut().insert(header::CONTENT_TYPE, mime);

-                res.set_body(AnyBody::Full {
-                    body: buf.into_inner().freeze(),
-                })
+                res.set_body(BoxBody::new(buf.into_inner()))
            }

            InternalErrorType::Response(ref resp) => {
--- a/src/error/mod.rs
+++ b/src/error/mod.rs
@@ -1,4 +1,5 @@
 //! Error and Result module
+
 // This is meant to be a glob import of the whole error module except for `Error`. Rustdoc can't yet
 // correctly resolve the conflicting `Error` type defined in this module, so these re-exports are
 // expanded manually.
--- a/src/error/response_error.rs
+++ b/src/error/response_error.rs
@@ -8,13 +8,12 @@ use std::{

 use actix_http::{
    body::BoxBody,
-    header::{self, IntoHeaderValue},
+    header::{self, TryIntoHeaderValue},
    Response, StatusCode,
 };
 use bytes::BytesMut;

 use crate::{
-    any_body::AnyBody,
    error::{downcast_dyn, downcast_get_type_id},
    helpers, HttpResponse,
 };
@@ -34,7 +33,7 @@ pub trait ResponseError: fmt::Debug + fmt::Display {
    ///
    /// By default, the generated response uses a 500 Internal Server Error status code, a
    /// `Content-Type` of `text/plain`, and the body is set to `Self`'s `Display` impl.
-    fn error_response(&self) -> HttpResponse {
+    fn error_response(&self) -> HttpResponse<BoxBody> {
        let mut res = HttpResponse::new(self.status_code());

        let mut buf = BytesMut::new();
@@ -43,7 +42,7 @@ pub trait ResponseError: fmt::Debug + fmt::Display {
        let mime = mime::TEXT_PLAIN_UTF_8.try_into_value().unwrap();
        res.headers_mut().insert(header::CONTENT_TYPE, mime);

-        res.set_body(AnyBody::Full { body: buf.freeze() })
+        res.set_body(BoxBody::new(buf))
    }

    downcast_get_type_id!();
@@ -51,7 +50,7 @@ pub trait ResponseError: fmt::Debug + fmt::Display {

 downcast_dyn!(ResponseError);

-impl ResponseError for Box<dyn StdError> {}
+impl ResponseError for Box<dyn StdError + 'static> {}

 #[cfg(feature = "openssl")]
 impl ResponseError for actix_tls::accept::openssl::reexports::Error {}
@@ -129,15 +128,7 @@ impl ResponseError for actix_http::error::ContentTypeError {

 impl ResponseError for actix_http::ws::HandshakeError {
    fn error_response(&self) -> HttpResponse<BoxBody> {
-        Response::from(self)
-            .map_body(|_, body| AnyBody::Boxed { body })
-            .into()
-    }
-}
-
-impl ResponseError for actix_http::error::EncoderError {
-    fn error_response(&self) -> HttpResponse {
-        todo!("")
+        Response::from(self).map_into_boxed_body().into()
    }
 }

--- a/src/http/header/content_disposition.rs
+++ b/src/http/header/content_disposition.rs
@@ -14,7 +14,7 @@ use once_cell::sync::Lazy;
 use regex::Regex;
 use std::fmt::{self, Write};

-use super::{ExtendedValue, Header, IntoHeaderValue, Writer};
+use super::{ExtendedValue, Header, TryIntoHeaderValue, Writer};
 use crate::http::header;

 /// Split at the index of the first `needle` if it exists or at the end.
@@ -454,7 +454,7 @@ impl ContentDisposition {
    }
 }

-impl IntoHeaderValue for ContentDisposition {
+impl TryIntoHeaderValue for ContentDisposition {
    type Error = header::InvalidHeaderValue;

    fn try_into_value(self) -> Result<header::HeaderValue, Self::Error> {
--- a/src/http/header/content_range.rs
+++ b/src/http/header/content_range.rs
@@ -3,7 +3,7 @@ use std::{
    str::FromStr,
 };

-use super::{HeaderValue, IntoHeaderValue, InvalidHeaderValue, Writer, CONTENT_RANGE};
+use super::{HeaderValue, InvalidHeaderValue, TryIntoHeaderValue, Writer, CONTENT_RANGE};
 use crate::error::ParseError;

 crate::http::header::common_header! {
@@ -196,7 +196,7 @@ impl Display for ContentRangeSpec {
    }
 }

-impl IntoHeaderValue for ContentRangeSpec {
+impl TryIntoHeaderValue for ContentRangeSpec {
    type Error = InvalidHeaderValue;

    fn try_into_value(self) -> Result<HeaderValue, Self::Error> {
--- a/src/http/header/entity.rs
+++ b/src/http/header/entity.rs
@@ -3,7 +3,7 @@ use std::{
    str::FromStr,
 };

-use super::{HeaderValue, IntoHeaderValue, InvalidHeaderValue, Writer};
+use super::{HeaderValue, InvalidHeaderValue, TryIntoHeaderValue, Writer};

 /// check that each char in the slice is either:
 /// 1. `%x21`, or
@@ -159,7 +159,7 @@ impl FromStr for EntityTag {
    }
 }

-impl IntoHeaderValue for EntityTag {
+impl TryIntoHeaderValue for EntityTag {
    type Error = InvalidHeaderValue;

    fn try_into_value(self) -> Result<HeaderValue, Self::Error> {
--- a/src/http/header/if_range.rs
+++ b/src/http/header/if_range.rs
@@ -1,8 +1,8 @@
 use std::fmt::{self, Display, Write};

 use super::{
-    from_one_raw_str, EntityTag, Header, HeaderName, HeaderValue, HttpDate, IntoHeaderValue,
-    InvalidHeaderValue, Writer,
+    from_one_raw_str, EntityTag, Header, HeaderName, HeaderValue, HttpDate, InvalidHeaderValue,
+    TryIntoHeaderValue, Writer,
 };
 use crate::error::ParseError;
 use crate::http::header;
@@ -96,7 +96,7 @@ impl Display for IfRange {
    }
 }

-impl IntoHeaderValue for IfRange {
+impl TryIntoHeaderValue for IfRange {
    type Error = InvalidHeaderValue;

    fn try_into_value(self) -> Result<HeaderValue, Self::Error> {
--- a/src/http/header/macros.rs
+++ b/src/http/header/macros.rs
@@ -125,7 +125,7 @@ macro_rules! common_header {
            }
        }

-        impl $crate::http::header::IntoHeaderValue for $id {
+        impl $crate::http::header::TryIntoHeaderValue for $id {
            type Error = $crate::http::header::InvalidHeaderValue;

            #[inline]
@@ -172,7 +172,7 @@ macro_rules! common_header {
            }
        }

-        impl $crate::http::header::IntoHeaderValue for $id {
+        impl $crate::http::header::TryIntoHeaderValue for $id {
            type Error = $crate::http::header::InvalidHeaderValue;

            #[inline]
@@ -211,7 +211,7 @@ macro_rules! common_header {
            }
        }

-        impl $crate::http::header::IntoHeaderValue for $id {
+        impl $crate::http::header::TryIntoHeaderValue for $id {
            type Error = $crate::http::header::InvalidHeaderValue;

            #[inline]
@@ -266,7 +266,7 @@ macro_rules! common_header {
            }
        }

-        impl $crate::http::header::IntoHeaderValue for $id {
+        impl $crate::http::header::TryIntoHeaderValue for $id {
            type Error = $crate::http::header::InvalidHeaderValue;

            #[inline]
--- a/src/http/header/range.rs
+++ b/src/http/header/range.rs
@@ -6,7 +6,7 @@ use std::{

 use actix_http::{error::ParseError, header, HttpMessage};

-use super::{Header, HeaderName, HeaderValue, IntoHeaderValue, InvalidHeaderValue, Writer};
+use super::{Header, HeaderName, HeaderValue, InvalidHeaderValue, TryIntoHeaderValue, Writer};

 /// `Range` header, defined
 /// in [RFC 7233 §3.1](https://datatracker.ietf.org/doc/html/rfc7233#section-3.1)
@@ -274,7 +274,7 @@ impl Header for Range {
    }
 }

-impl IntoHeaderValue for Range {
+impl TryIntoHeaderValue for Range {
    type Error = InvalidHeaderValue;

    fn try_into_value(self) -> Result<HeaderValue, Self::Error> {
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -70,7 +70,6 @@
 #![doc(html_logo_url = "https://actix.rs/img/logo.png")]
 #![doc(html_favicon_url = "https://actix.rs/favicon.ico")]

-mod any_body;
 mod app;
 mod app_service;
 mod config;
@@ -87,7 +86,6 @@ pub mod middleware;
 mod request;
 mod request_data;
 mod resource;
-mod responder;
 mod response;
 mod rmap;
 mod route;
@@ -110,12 +108,10 @@ pub use crate::error::{Error, ResponseError, Result};
 pub use crate::extract::FromRequest;
 pub use crate::request::HttpRequest;
 pub use crate::resource::Resource;
-pub use crate::responder::Responder;
-pub use crate::response::{HttpResponse, HttpResponseBuilder};
+pub use crate::response::{CustomizeResponder, HttpResponse, HttpResponseBuilder, Responder};
 pub use crate::route::Route;
 pub use crate::scope::Scope;
 pub use crate::server::HttpServer;
-// TODO: is exposing the error directly really needed
-pub use crate::types::{Either, EitherExtractError};
+pub use crate::types::Either;

 pub(crate) type BoxError = Box<dyn std::error::Error>;
--- a/src/middleware/compress.rs
+++ b/src/middleware/compress.rs
@@ -10,7 +10,7 @@ use std::{
 };

 use actix_http::{
-    body::MessageBody,
+    body::{EitherBody, MessageBody},
    encoding::Encoder,
    header::{ContentEncoding, ACCEPT_ENCODING},
    StatusCode,
@@ -22,7 +22,6 @@ use once_cell::sync::Lazy;
 use pin_project_lite::pin_project;

 use crate::{
-    any_body::AnyBody,
    dev::BodyEncoding,
    service::{ServiceRequest, ServiceResponse},
    Error, HttpResponse,
@@ -62,7 +61,7 @@ where
    B: MessageBody,
    S: Service<ServiceRequest, Response = ServiceResponse<B>, Error = Error>,
 {
-    type Response = ServiceResponse<Encoder<AnyBody<B>>>;
+    type Response = ServiceResponse<EitherBody<Encoder<B>>>;
    type Error = Error;
    type Transform = CompressMiddleware<S>;
    type InitError = ();
@@ -112,7 +111,7 @@ where
    S: Service<ServiceRequest, Response = ServiceResponse<B>, Error = Error>,
    B: MessageBody,
 {
-    type Response = ServiceResponse<Encoder<AnyBody<B>>>;
+    type Response = ServiceResponse<EitherBody<Encoder<B>>>;
    type Error = Error;
    type Future = Either<CompressResponse<S, B>, Ready<Result<Self::Response, Self::Error>>>;

@@ -147,15 +146,12 @@ where
                let res = HttpResponse::with_body(
                    StatusCode::NOT_ACCEPTABLE,
                    SUPPORTED_ALGORITHM_NAMES.clone(),
-                )
-                .map_body(|_, body| match body {
-                    AnyBody::Full { body } => AnyBody::Stream {
-                        body: Encoder::not_acceptable(body),
-                    },
-                    _ => unreachable!("probably"),
-                });
+                );

-                Either::right(ok(req.into_response(res)))
+                Either::right(ok(req
+                    .into_response(res)
+                    .map_into_boxed_body()
+                    .map_into_right_body()))
            }
        }
    }
@@ -178,7 +174,7 @@ where
    B: MessageBody,
    S: Service<ServiceRequest, Response = ServiceResponse<B>, Error = Error>,
 {
-    type Output = Result<ServiceResponse<Encoder<AnyBody<B>>>, Error>;
+    type Output = Result<ServiceResponse<EitherBody<Encoder<B>>>, Error>;

    fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
        let this = self.project();
@@ -191,8 +187,8 @@ where
                    *this.encoding
                };

-                Poll::Ready(Ok(resp.map_body(move |head, body| AnyBody::Stream {
-                    body: Encoder::response(enc, head, body),
+                Poll::Ready(Ok(resp.map_body(move |head, body| {
+                    EitherBody::left(Encoder::response(enc, head, body))
                })))
            }

--- a/src/middleware/default_headers.rs
+++ b/src/middleware/default_headers.rs
@@ -16,7 +16,7 @@ use pin_project_lite::pin_project;

 use crate::{
    dev::{Service, Transform},
-    http::header::{HeaderMap, HeaderName, HeaderValue, CONTENT_TYPE},
+    http::header::{HeaderMap, HeaderName, HeaderValue, TryIntoHeaderPair, CONTENT_TYPE},
    service::{ServiceRequest, ServiceResponse},
    Error,
 };
@@ -29,79 +29,81 @@ use crate::{
 /// ```
 /// use actix_web::{web, http, middleware, App, HttpResponse};
 ///
-/// fn main() {
-///     let app = App::new()
-///         .wrap(middleware::DefaultHeaders::new().header("X-Version", "0.2"))
-///         .service(
-///             web::resource("/test")
-///                 .route(web::get().to(|| HttpResponse::Ok()))
-///                 .route(web::method(http::Method::HEAD).to(|| HttpResponse::MethodNotAllowed()))
-///         );
-/// }
+/// let app = App::new()
+///     .wrap(middleware::DefaultHeaders::new().add(("X-Version", "0.2")))
+///     .service(
+///         web::resource("/test")
+///             .route(web::get().to(|| HttpResponse::Ok()))
+///             .route(web::method(http::Method::HEAD).to(|| HttpResponse::MethodNotAllowed()))
+///     );
 /// ```
-#[derive(Clone)]
+#[derive(Debug, Clone, Default)]
 pub struct DefaultHeaders {
    inner: Rc<Inner>,
 }

+#[derive(Debug, Default)]
 struct Inner {
    headers: HeaderMap,
 }

-impl Default for DefaultHeaders {
-    fn default() -> Self {
-        DefaultHeaders {
-            inner: Rc::new(Inner {
-                headers: HeaderMap::new(),
-            }),
-        }
-    }
-}
-
 impl DefaultHeaders {
    /// Constructs an empty `DefaultHeaders` middleware.
+    #[inline]
    pub fn new() -> DefaultHeaders {
        DefaultHeaders::default()
    }

    /// Adds a header to the default set.
-    #[inline]
-    pub fn header<K, V>(mut self, key: K, value: V) -> Self
+    ///
+    /// # Panics
+    /// Panics when resolved header name or value is invalid.
+    #[allow(clippy::should_implement_trait)]
+    pub fn add(mut self, header: impl TryIntoHeaderPair) -> Self {
+        // standard header terminology `insert` or `append` for this method would make the behavior
+        // of this middleware less obvious since it only adds the headers if they are not present
+
+        match header.try_into_pair() {
+            Ok((key, value)) => Rc::get_mut(&mut self.inner)
+                .expect("All default headers must be added before cloning.")
+                .headers
+                .append(key, value),
+            Err(err) => panic!("Invalid header: {}", err.into()),
+        }
+
+        self
+    }
+
+    #[doc(hidden)]
+    #[deprecated(
+        since = "4.0.0",
+        note = "Prefer `.add((key, value))`. Will be removed in v5."
+    )]
+    pub fn header<K, V>(self, key: K, value: V) -> Self
    where
        HeaderName: TryFrom<K>,
        <HeaderName as TryFrom<K>>::Error: Into<HttpError>,
        HeaderValue: TryFrom<V>,
        <HeaderValue as TryFrom<V>>::Error: Into<HttpError>,
    {
-        #[allow(clippy::match_wild_err_arm)]
-        match HeaderName::try_from(key) {
-            Ok(key) => match HeaderValue::try_from(value) {
-                Ok(value) => {
-                    Rc::get_mut(&mut self.inner)
-                        .expect("Multiple copies exist")
-                        .headers
-                        .append(key, value);
-                }
-                Err(_) => panic!("Can not create header value"),
-            },
-            Err(_) => panic!("Can not create header name"),
-        }
-        self
+        self.add((
+            HeaderName::try_from(key)
+                .map_err(Into::into)
+                .expect("Invalid header name"),
+            HeaderValue::try_from(value)
+                .map_err(Into::into)
+                .expect("Invalid header value"),
+        ))
    }

    /// Adds a default *Content-Type* header if response does not contain one.
    ///
    /// Default is `application/octet-stream`.
-    pub fn add_content_type(mut self) -> Self {
-        Rc::get_mut(&mut self.inner)
-            .expect("Multiple `Inner` copies exist.")
-            .headers
-            .insert(
-                CONTENT_TYPE,
-                HeaderValue::from_static("application/octet-stream"),
-            );
-
-        self
+    pub fn add_content_type(self) -> Self {
+        self.add((
+            CONTENT_TYPE,
+            HeaderValue::from_static("application/octet-stream"),
+        ))
    }
 }

@@ -119,7 +121,7 @@ where
    fn new_transform(&self, service: S) -> Self::Future {
        ready(Ok(DefaultHeadersMiddleware {
            service,
-            inner: self.inner.clone(),
+            inner: Rc::clone(&self.inner),
        }))
    }
 }
@@ -197,17 +199,22 @@ mod tests {
    };

    #[actix_rt::test]
-    async fn test_default_headers() {
+    async fn adding_default_headers() {
        let mw = DefaultHeaders::new()
-            .header(CONTENT_TYPE, "0001")
+            .add(("X-TEST", "0001"))
+            .add(("X-TEST-TWO", HeaderValue::from_static("123")))
            .new_transform(ok_service())
            .await
            .unwrap();

        let req = TestRequest::default().to_srv_request();
-        let resp = mw.call(req).await.unwrap();
-        assert_eq!(resp.headers().get(CONTENT_TYPE).unwrap(), "0001");
+        let res = mw.call(req).await.unwrap();
+        assert_eq!(res.headers().get("x-test").unwrap(), "0001");
+        assert_eq!(res.headers().get("x-test-two").unwrap(), "123");
+    }

+    #[actix_rt::test]
+    async fn no_override_existing() {
        let req = TestRequest::default().to_srv_request();
        let srv = |req: ServiceRequest| {
            ok(req.into_response(
@@ -217,7 +224,7 @@ mod tests {
            ))
        };
        let mw = DefaultHeaders::new()
-            .header(CONTENT_TYPE, "0001")
+            .add((CONTENT_TYPE, "0001"))
            .new_transform(srv.into_service())
            .await
            .unwrap();
@@ -226,7 +233,7 @@ mod tests {
    }

    #[actix_rt::test]
-    async fn test_content_type() {
+    async fn adding_content_type() {
        let srv = |req: ServiceRequest| ok(req.into_response(HttpResponse::Ok().finish()));
        let mw = DefaultHeaders::new()
            .add_content_type()
@@ -241,4 +248,16 @@ mod tests {
            "application/octet-stream"
        );
    }
+
+    #[test]
+    #[should_panic]
+    fn invalid_header_name() {
+        DefaultHeaders::new().add((":", "hello"));
+    }
+
+    #[test]
+    #[should_panic]
+    fn invalid_header_value() {
+        DefaultHeaders::new().add(("x-test", "\n"));
+    }
 }
--- a/src/middleware/logger.rs
+++ b/src/middleware/logger.rs
@@ -22,7 +22,6 @@ use regex::{Regex, RegexSet};
 use time::{format_description::well_known::Rfc3339, OffsetDateTime};

 use crate::{
-    any_body::AnyBody,
    body::{BodySize, MessageBody},
    http::header::HeaderName,
    service::{ServiceRequest, ServiceResponse},
@@ -176,7 +175,7 @@ impl Default for Logger {
    }
 }

-impl<S, B: 'static> Transform<S, ServiceRequest> for Logger
+impl<S, B> Transform<S, ServiceRequest> for Logger
 where
    S: Service<ServiceRequest, Response = ServiceResponse<B>, Error = Error>,
    B: MessageBody,
@@ -211,7 +210,7 @@ pub struct LoggerMiddleware<S> {
    service: S,
 }

-impl<S, B: 'static> Service<ServiceRequest> for LoggerMiddleware<S>
+impl<S, B> Service<ServiceRequest> for LoggerMiddleware<S>
 where
    S: Service<ServiceRequest, Response = ServiceResponse<B>, Error = Error>,
    B: MessageBody,
@@ -263,7 +262,7 @@ pin_project! {
    }
 }

-impl<S, B: 'static> Future for LoggerResponse<S, B>
+impl<S, B> Future for LoggerResponse<S, B>
 where
    B: MessageBody,
    S: Service<ServiceRequest, Response = ServiceResponse<B>, Error = Error>,
@@ -291,13 +290,11 @@ where
        let time = *this.time;
        let format = this.format.take();

-        Poll::Ready(Ok(res.map_body(move |_, body| AnyBody::Stream {
-            body: StreamLog {
-                body: body.into_body(),
-                time,
-                format,
-                size: 0,
-            },
+        Poll::Ready(Ok(res.map_body(move |_, body| StreamLog {
+            body,
+            time,
+            format,
+            size: 0,
        })))
    }
 }
@@ -305,7 +302,7 @@ where
 pin_project! {
    pub struct StreamLog<B> {
        #[pin]
-        body: AnyBody<B>,
+        body: B,
        format: Option<Format>,
        size: usize,
        time: OffsetDateTime,
--- a/src/middleware/mod.rs
+++ b/src/middleware/mod.rs
@@ -33,7 +33,7 @@ mod tests {
        let _ = App::new()
            .wrap(Compat::new(Logger::default()))
            .wrap(Condition::new(true, DefaultHeaders::new()))
-            .wrap(DefaultHeaders::new().header("X-Test2", "X-Value2"))
+            .wrap(DefaultHeaders::new().add(("X-Test2", "X-Value2")))
            .wrap(ErrorHandlers::new().handler(StatusCode::FORBIDDEN, |res| {
                Ok(ErrorHandlerResponse::Response(res))
            }))
@@ -46,7 +46,7 @@ mod tests {
            .wrap(ErrorHandlers::new().handler(StatusCode::FORBIDDEN, |res| {
                Ok(ErrorHandlerResponse::Response(res))
            }))
-            .wrap(DefaultHeaders::new().header("X-Test2", "X-Value2"))
+            .wrap(DefaultHeaders::new().add(("X-Test2", "X-Value2")))
            .wrap(Condition::new(true, DefaultHeaders::new()))
            .wrap(Compat::new(Logger::default()));

--- a/src/request.rs
+++ b/src/request.rs
@@ -349,7 +349,7 @@ impl Drop for HttpRequest {
    fn drop(&mut self) {
        // if possible, contribute to current worker's HttpRequest allocation pool

-        // This relies on no Weak<HttpRequestInner> exists anywhere. (There is none.)
+        // This relies on no weak references to inner existing anywhere within the codebase.
        if let Some(inner) = Rc::get_mut(&mut self.inner) {
            if inner.app_state.pool().is_available() {
                // clear additional app_data and keep the root one for reuse.
@@ -360,7 +360,7 @@ impl Drop for HttpRequest {
                Rc::get_mut(&mut inner.req_data).unwrap().get_mut().clear();

                // a re-borrow of pool is necessary here.
-                let req = self.inner.clone();
+                let req = Rc::clone(&self.inner);
                self.app_state().pool().push(req);
            }
        }
--- a/src/request_data.rs
+++ b/src/request_data.rs
@@ -17,7 +17,7 @@ use crate::{dev::Payload, error::ErrorInternalServerError, Error, FromRequest, H
 /// # Mutating Request Data
 /// Note that since extractors must output owned data, only types that `impl Clone` can use this
 /// extractor. A clone is taken of the required request data and can, therefore, not be directly
-/// mutated in-place. To mutate request data, continue to use [`HttpRequest::extensions_mut`] or
+/// mutated in-place. To mutate request data, continue to use [`HttpRequest::req_data_mut`] or
 /// re-insert the cloned data back into the extensions map. A `DerefMut` impl is intentionally not
 /// provided to make this potential foot-gun more obvious.
 ///
--- a/src/resource.rs
+++ b/src/resource.rs
@@ -15,13 +15,12 @@ use crate::{
    dev::{ensure_leading_slash, AppService, ResourceDef},
    guard::Guard,
    handler::Handler,
-    responder::Responder,
    route::{Route, RouteService},
    service::{
        BoxedHttpService, BoxedHttpServiceFactory, HttpServiceFactory, ServiceRequest,
        ServiceResponse,
    },
-    BoxError, Error, FromRequest, HttpResponse,
+    BoxError, Error, FromRequest, HttpResponse, Responder,
 };

 /// *Resource* is an entry in resources table which corresponds to requested URL.
@@ -526,7 +525,7 @@ mod tests {
                    .name("test")
                    .wrap(
                        DefaultHeaders::new()
-                            .header(header::CONTENT_TYPE, HeaderValue::from_static("0001")),
+                            .add((header::CONTENT_TYPE, HeaderValue::from_static("0001"))),
                    )
                    .route(web::get().to(HttpResponse::Ok)),
            ),
--- a/src/response/builder.rs
+++ b/src/response/builder.rs
@@ -9,7 +9,7 @@ use std::{
 use actix_http::{
    body::{BodyStream, BoxBody, MessageBody},
    error::HttpError,
-    header::{self, HeaderName, IntoHeaderPair, IntoHeaderValue},
+    header::{self, HeaderName, TryIntoHeaderPair, TryIntoHeaderValue},
    ConnectionType, Extensions, Response, ResponseHead, StatusCode,
 };
 use bytes::Bytes;
@@ -22,7 +22,6 @@ use actix_http::header::HeaderValue;
 use cookie::{Cookie, CookieJar};

 use crate::{
-    any_body::AnyBody,
    error::{Error, JsonPayloadError},
    BoxError, HttpResponse,
 };
@@ -68,12 +67,9 @@ impl HttpResponseBuilder {
    ///     .insert_header(("X-TEST", "value"))
    ///     .finish();
    /// ```
-    pub fn insert_header<H>(&mut self, header: H) -> &mut Self
-    where
-        H: IntoHeaderPair,
-    {
+    pub fn insert_header(&mut self, header: impl TryIntoHeaderPair) -> &mut Self {
        if let Some(parts) = self.inner() {
-            match header.try_into_header_pair() {
+            match header.try_into_pair() {
                Ok((key, value)) => {
                    parts.headers.insert(key, value);
                }
@@ -95,12 +91,9 @@ impl HttpResponseBuilder {
    ///     .append_header(("X-TEST", "value2"))
    ///     .finish();
    /// ```
-    pub fn append_header<H>(&mut self, header: H) -> &mut Self
-    where
-        H: IntoHeaderPair,
-    {
+    pub fn append_header(&mut self, header: impl TryIntoHeaderPair) -> &mut Self {
        if let Some(parts) = self.inner() {
-            match header.try_into_header_pair() {
+            match header.try_into_pair() {
                Ok((key, value)) => parts.headers.append(key, value),
                Err(e) => self.err = Some(e.into()),
            };
@@ -119,7 +112,7 @@ impl HttpResponseBuilder {
    where
        K: TryInto<HeaderName>,
        K::Error: Into<HttpError>,
-        V: IntoHeaderValue,
+        V: TryIntoHeaderValue,
    {
        if self.err.is_some() {
            return self;
@@ -144,7 +137,7 @@ impl HttpResponseBuilder {
    where
        K: TryInto<HeaderName>,
        K::Error: Into<HttpError>,
-        V: IntoHeaderValue,
+        V: TryIntoHeaderValue,
    {
        if self.err.is_some() {
            return self;
@@ -181,7 +174,7 @@ impl HttpResponseBuilder {
    #[inline]
    pub fn upgrade<V>(&mut self, value: V) -> &mut Self
    where
-        V: IntoHeaderValue,
+        V: TryIntoHeaderValue,
    {
        if let Some(parts) = self.inner() {
            parts.set_connection_type(ConnectionType::Upgrade);
@@ -219,7 +212,7 @@ impl HttpResponseBuilder {
    #[inline]
    pub fn content_type<V>(&mut self, value: V) -> &mut Self
    where
-        V: IntoHeaderValue,
+        V: TryIntoHeaderValue,
    {
        if let Some(parts) = self.inner() {
            match value.try_into_value() {
@@ -334,7 +327,7 @@ impl HttpResponseBuilder {
            .set_body(body);

        #[allow(unused_mut)] // mut is only unused when cookies are disabled
-        let mut res = HttpResponse::from(res.map_body(|_, body| AnyBody::Stream { body }));
+        let mut res = HttpResponse::from(res);

        #[cfg(feature = "cookies")]
        if let Some(ref jar) = self.cookies {
@@ -417,7 +410,7 @@ impl From<HttpResponseBuilder> for HttpResponse {
    }
 }

-impl From<HttpResponseBuilder> for Response<AnyBody<BoxBody>> {
+impl From<HttpResponseBuilder> for Response<BoxBody> {
    fn from(mut builder: HttpResponseBuilder) -> Self {
        builder.finish().into()
    }
--- a/src/response/customize_responder.rs
+++ b/src/response/customize_responder.rs
@@ -0,0 +1,245 @@
+use actix_http::{
+    body::{EitherBody, MessageBody},
+    error::HttpError,
+    header::HeaderMap,
+    header::TryIntoHeaderPair,
+    StatusCode,
+};
+
+use crate::{BoxError, HttpRequest, HttpResponse, Responder};
+
+/// Allows overriding status code and headers for a [`Responder`].
+///
+/// Created by the [`Responder::customize`] method.
+pub struct CustomizeResponder<R> {
+    inner: CustomizeResponderInner<R>,
+    error: Option<HttpError>,
+}
+
+struct CustomizeResponderInner<R> {
+    responder: R,
+    status: Option<StatusCode>,
+    override_headers: HeaderMap,
+    append_headers: HeaderMap,
+}
+
+impl<R: Responder> CustomizeResponder<R> {
+    pub(crate) fn new(responder: R) -> Self {
+        CustomizeResponder {
+            inner: CustomizeResponderInner {
+                responder,
+                status: None,
+                override_headers: HeaderMap::new(),
+                append_headers: HeaderMap::new(),
+            },
+            error: None,
+        }
+    }
+
+    /// Override a status code for the Responder's response.
+    ///
+    /// # Examples
+    /// ```
+    /// use actix_web::{Responder, http::StatusCode, test::TestRequest};
+    ///
+    /// let responder = "Welcome!".customize().with_status(StatusCode::ACCEPTED);
+    ///
+    /// let request = TestRequest::default().to_http_request();
+    /// let response = responder.respond_to(&request);
+    /// assert_eq!(response.status(), StatusCode::ACCEPTED);
+    /// ```
+    pub fn with_status(mut self, status: StatusCode) -> Self {
+        if let Some(inner) = self.inner() {
+            inner.status = Some(status);
+        }
+
+        self
+    }
+
+    /// Insert (override) header in the final response.
+    ///
+    /// Overrides other headers with the same name.
+    /// See [`HeaderMap::insert`](crate::http::header::HeaderMap::insert).
+    ///
+    /// Headers added with this method will be inserted before those added
+    /// with [`append_header`](Self::append_header). As such, header(s) can be overridden with more
+    /// than one new header by first calling `insert_header` followed by `append_header`.
+    ///
+    /// # Examples
+    /// ```
+    /// use actix_web::{Responder, test::TestRequest};
+    ///
+    /// let responder = "Hello world!"
+    ///     .customize()
+    ///     .insert_header(("x-version", "1.2.3"));
+    ///
+    /// let request = TestRequest::default().to_http_request();
+    /// let response = responder.respond_to(&request);
+    /// assert_eq!(response.headers().get("x-version").unwrap(), "1.2.3");
+    /// ```
+    pub fn insert_header(mut self, header: impl TryIntoHeaderPair) -> Self {
+        if let Some(inner) = self.inner() {
+            match header.try_into_pair() {
+                Ok((key, value)) => {
+                    inner.override_headers.insert(key, value);
+                }
+                Err(err) => self.error = Some(err.into()),
+            };
+        }
+
+        self
+    }
+
+    /// Append header to the final response.
+    ///
+    /// Unlike [`insert_header`](Self::insert_header), this will not override existing headers.
+    /// See [`HeaderMap::append`](crate::http::header::HeaderMap::append).
+    ///
+    /// Headers added here are appended _after_ additions/overrides from `insert_header`.
+    ///
+    /// # Examples
+    /// ```
+    /// use actix_web::{Responder, test::TestRequest};
+    ///
+    /// let responder = "Hello world!"
+    ///     .customize()
+    ///     .append_header(("x-version", "1.2.3"));
+    ///
+    /// let request = TestRequest::default().to_http_request();
+    /// let response = responder.respond_to(&request);
+    /// assert_eq!(response.headers().get("x-version").unwrap(), "1.2.3");
+    /// ```
+    pub fn append_header(mut self, header: impl TryIntoHeaderPair) -> Self {
+        if let Some(inner) = self.inner() {
+            match header.try_into_pair() {
+                Ok((key, value)) => {
+                    inner.append_headers.append(key, value);
+                }
+                Err(err) => self.error = Some(err.into()),
+            };
+        }
+
+        self
+    }
+
+    #[doc(hidden)]
+    #[deprecated(since = "4.0.0", note = "Renamed to `insert_header`.")]
+    pub fn with_header(self, header: impl TryIntoHeaderPair) -> Self
+    where
+        Self: Sized,
+    {
+        self.insert_header(header)
+    }
+
+    fn inner(&mut self) -> Option<&mut CustomizeResponderInner<R>> {
+        if self.error.is_some() {
+            None
+        } else {
+            Some(&mut self.inner)
+        }
+    }
+}
+
+impl<T> Responder for CustomizeResponder<T>
+where
+    T: Responder,
+    <T::Body as MessageBody>::Error: Into<BoxError>,
+{
+    type Body = EitherBody<T::Body>;
+
+    fn respond_to(self, req: &HttpRequest) -> HttpResponse<Self::Body> {
+        if let Some(err) = self.error {
+            return HttpResponse::from_error(err).map_into_right_body();
+        }
+
+        let mut res = self.inner.responder.respond_to(req);
+
+        if let Some(status) = self.inner.status {
+            *res.status_mut() = status;
+        }
+
+        for (k, v) in self.inner.override_headers {
+            res.headers_mut().insert(k, v);
+        }
+
+        for (k, v) in self.inner.append_headers {
+            res.headers_mut().append(k, v);
+        }
+
+        res.map_into_left_body()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use bytes::Bytes;
+
+    use actix_http::body::to_bytes;
+
+    use super::*;
+    use crate::{
+        http::{
+            header::{HeaderValue, CONTENT_TYPE},
+            StatusCode,
+        },
+        test::TestRequest,
+    };
+
+    #[actix_rt::test]
+    async fn customize_responder() {
+        let req = TestRequest::default().to_http_request();
+        let res = "test"
+            .to_string()
+            .customize()
+            .with_status(StatusCode::BAD_REQUEST)
+            .respond_to(&req);
+
+        assert_eq!(res.status(), StatusCode::BAD_REQUEST);
+        assert_eq!(
+            to_bytes(res.into_body()).await.unwrap(),
+            Bytes::from_static(b"test"),
+        );
+
+        let res = "test"
+            .to_string()
+            .customize()
+            .insert_header(("content-type", "json"))
+            .respond_to(&req);
+
+        assert_eq!(res.status(), StatusCode::OK);
+        assert_eq!(
+            res.headers().get(CONTENT_TYPE).unwrap(),
+            HeaderValue::from_static("json")
+        );
+        assert_eq!(
+            to_bytes(res.into_body()).await.unwrap(),
+            Bytes::from_static(b"test"),
+        );
+    }
+
+    #[actix_rt::test]
+    async fn tuple_responder_with_status_code() {
+        let req = TestRequest::default().to_http_request();
+        let res = ("test".to_string(), StatusCode::BAD_REQUEST).respond_to(&req);
+        assert_eq!(res.status(), StatusCode::BAD_REQUEST);
+        assert_eq!(
+            to_bytes(res.into_body()).await.unwrap(),
+            Bytes::from_static(b"test"),
+        );
+
+        let req = TestRequest::default().to_http_request();
+        let res = ("test".to_string(), StatusCode::OK)
+            .customize()
+            .insert_header((CONTENT_TYPE, mime::APPLICATION_JSON))
+            .respond_to(&req);
+        assert_eq!(res.status(), StatusCode::OK);
+        assert_eq!(
+            res.headers().get(CONTENT_TYPE).unwrap(),
+            HeaderValue::from_static("application/json")
+        );
+        assert_eq!(
+            to_bytes(res.into_body()).await.unwrap(),
+            Bytes::from_static(b"test"),
+        );
+    }
+}
--- a/src/response/mod.rs
+++ b/src/response/mod.rs
@@ -1,9 +1,13 @@
 mod builder;
+mod customize_responder;
 mod http_codes;
+mod responder;
 #[allow(clippy::module_inception)]
 mod response;

 pub use self::builder::HttpResponseBuilder;
+pub use self::customize_responder::CustomizeResponder;
+pub use self::responder::Responder;
 pub use self::response::HttpResponse;

 #[cfg(feature = "cookies")]
--- a/src/response/responder.rs
+++ b/src/response/responder.rs
@@ -1,67 +1,59 @@
 use std::borrow::Cow;

 use actix_http::{
-    body::{BoxBody, MessageBody},
-    error::HttpError,
-    header::HeaderMap,
-    header::IntoHeaderPair,
+    body::{BoxBody, EitherBody, MessageBody},
+    header::TryIntoHeaderPair,
    StatusCode,
 };
 use bytes::{Bytes, BytesMut};

-use crate::{
-    any_body::AnyBody, BoxError, Error, HttpRequest, HttpResponse, HttpResponseBuilder,
-};
+use crate::{BoxError, Error, HttpRequest, HttpResponse, HttpResponseBuilder};
+
+use super::CustomizeResponder;

 /// Trait implemented by types that can be converted to an HTTP response.
 ///
 /// Any types that implement this trait can be used in the return type of a handler.
+// # TODO: more about implementation notes and foreign impls
 pub trait Responder {
    type Body: MessageBody + 'static;

    /// Convert self to `HttpResponse`.
    fn respond_to(self, req: &HttpRequest) -> HttpResponse<Self::Body>;

-    /// Override a status code for a Responder.
+    /// Wraps responder to allow alteration of its response.
    ///
-    /// ```
-    /// use actix_web::{http::StatusCode, HttpRequest, Responder};
+    /// See [`CustomizeResponder`] docs for its capabilities.
    ///
-    /// fn index(req: HttpRequest) -> impl Responder {
-    ///     "Welcome!".with_status(StatusCode::OK)
-    /// }
+    /// # Examples
    /// ```
-    fn with_status(self, status: StatusCode) -> CustomResponder<Self>
+    /// use actix_web::{Responder, http::StatusCode, test::TestRequest};
+    ///
+    /// let responder = "Hello world!"
+    ///     .customize()
+    ///     .with_status(StatusCode::BAD_REQUEST)
+    ///     .insert_header(("x-hello", "world"));
+    ///
+    /// let request = TestRequest::default().to_http_request();
+    /// let response = responder.respond_to(&request);
+    /// assert_eq!(response.status(), StatusCode::BAD_REQUEST);
+    /// assert_eq!(response.headers().get("x-hello").unwrap(), "world");
+    /// ```
+    #[inline]
+    fn customize(self) -> CustomizeResponder<Self>
    where
        Self: Sized,
    {
-        CustomResponder::new(self).with_status(status)
+        CustomizeResponder::new(self)
    }

-    /// Insert header to the final response.
-    ///
-    /// Overrides other headers with the same name.
-    ///
-    /// ```
-    /// use actix_web::{web, HttpRequest, Responder};
-    /// use serde::Serialize;
-    ///
-    /// #[derive(Serialize)]
-    /// struct MyObj {
-    ///     name: String,
-    /// }
-    ///
-    /// fn index(req: HttpRequest) -> impl Responder {
-    ///     web::Json(MyObj { name: "Name".to_owned() })
-    ///         .with_header(("x-version", "1.2.3"))
-    /// }
-    /// ```
-    fn with_header<H>(self, header: H) -> CustomResponder<Self>
+    #[doc(hidden)]
+    #[deprecated(since = "4.0.0", note = "Prefer `.customize().insert_header(header)`.")]
+    fn with_header(self, header: impl TryIntoHeaderPair) -> CustomizeResponder<Self>
    where
        Self: Sized,
-        H: IntoHeaderPair,
    {
-        CustomResponder::new(self).with_header(header)
+        self.customize().insert_header(header)
    }
 }

@@ -74,7 +66,7 @@ impl Responder for HttpResponse {
    }
 }

-impl Responder for actix_http::Response<AnyBody<BoxBody>> {
+impl Responder for actix_http::Response<BoxBody> {
    type Body = BoxBody;

    #[inline]
@@ -97,10 +89,7 @@ impl Responder for actix_http::ResponseBuilder {

    #[inline]
    fn respond_to(mut self, req: &HttpRequest) -> HttpResponse<Self::Body> {
-        self.finish()
-            .map_into_boxed_body()
-            .map_body(|_, body| AnyBody::Boxed { body })
-            .respond_to(req)
+        self.finish().map_into_boxed_body().respond_to(req)
    }
 }

@@ -109,12 +98,12 @@ where
    T: Responder,
    <T::Body as MessageBody>::Error: Into<BoxError>,
 {
-    type Body = T::Body;
+    type Body = EitherBody<T::Body>;

    fn respond_to(self, req: &HttpRequest) -> HttpResponse<Self::Body> {
        match self {
-            Some(val) => val.respond_to(req),
-            None => HttpResponse::new(StatusCode::NOT_FOUND).map_into_body(),
+            Some(val) => val.respond_to(req).map_into_left_body(),
+            None => HttpResponse::new(StatusCode::NOT_FOUND).map_into_right_body(),
        }
    }
 }
@@ -125,12 +114,12 @@ where
    <T::Body as MessageBody>::Error: Into<BoxError>,
    E: Into<Error>,
 {
-    type Body = T::Body;
+    type Body = EitherBody<T::Body>;

    fn respond_to(self, req: &HttpRequest) -> HttpResponse<Self::Body> {
        match self {
-            Ok(val) => val.respond_to(req),
-            Err(err) => HttpResponse::from_error(err.into()).map_into_body(),
+            Ok(val) => val.respond_to(req).map_into_left_body(),
+            Err(err) => HttpResponse::from_error(err.into()).map_into_right_body(),
        }
    }
 }
@@ -151,12 +140,7 @@ macro_rules! impl_responder_by_forward_into_base_response {
            type Body = $body;

            fn respond_to(self, _: &HttpRequest) -> HttpResponse<Self::Body> {
-                let res = actix_http::Response::with_body(
-                    StatusCode::default(),
-                    AnyBody::Full {
-                        body: Bytes::from(self),
-                    },
-                );
+                let res: actix_http::Response<_> = self.into();
                res.into()
            }
        }
@@ -181,12 +165,7 @@ macro_rules! impl_into_string_responder {

            fn respond_to(self, _: &HttpRequest) -> HttpResponse<Self::Body> {
                let string: String = self.into();
-                let res = actix_http::Response::with_body(
-                    StatusCode::default(),
-                    AnyBody::Full {
-                        body: Bytes::from(string),
-                    },
-                );
+                let res: actix_http::Response<_> = string.into();
                res.into()
            }
        }
@@ -196,98 +175,6 @@ macro_rules! impl_into_string_responder {
 impl_into_string_responder!(&'_ String);
 impl_into_string_responder!(Cow<'_, str>);

-/// Allows overriding status code and headers for a responder.
-pub struct CustomResponder<T> {
-    responder: T,
-    status: Option<StatusCode>,
-    headers: Result<HeaderMap, HttpError>,
-}
-
-impl<T: Responder> CustomResponder<T> {
-    fn new(responder: T) -> Self {
-        CustomResponder {
-            responder,
-            status: None,
-            headers: Ok(HeaderMap::new()),
-        }
-    }
-
-    /// Override a status code for the Responder's response.
-    ///
-    /// ```
-    /// use actix_web::{HttpRequest, Responder, http::StatusCode};
-    ///
-    /// fn index(req: HttpRequest) -> impl Responder {
-    ///     "Welcome!".with_status(StatusCode::OK)
-    /// }
-    /// ```
-    pub fn with_status(mut self, status: StatusCode) -> Self {
-        self.status = Some(status);
-        self
-    }
-
-    /// Insert header to the final response.
-    ///
-    /// Overrides other headers with the same name.
-    ///
-    /// ```
-    /// use actix_web::{web, HttpRequest, Responder};
-    /// use serde::Serialize;
-    ///
-    /// #[derive(Serialize)]
-    /// struct MyObj {
-    ///     name: String,
-    /// }
-    ///
-    /// fn index(req: HttpRequest) -> impl Responder {
-    ///     web::Json(MyObj { name: "Name".to_string() })
-    ///         .with_header(("x-version", "1.2.3"))
-    ///         .with_header(("x-version", "1.2.3"))
-    /// }
-    /// ```
-    pub fn with_header<H>(mut self, header: H) -> Self
-    where
-        H: IntoHeaderPair,
-    {
-        if let Ok(ref mut headers) = self.headers {
-            match header.try_into_header_pair() {
-                Ok((key, value)) => headers.append(key, value),
-                Err(e) => self.headers = Err(e.into()),
-            };
-        }
-
-        self
-    }
-}
-
-impl<T> Responder for CustomResponder<T>
-where
-    T: Responder,
-    <T::Body as MessageBody>::Error: Into<BoxError>,
-{
-    type Body = T::Body;
-
-    fn respond_to(self, req: &HttpRequest) -> HttpResponse<Self::Body> {
-        let headers = match self.headers {
-            Ok(headers) => headers,
-            Err(err) => return HttpResponse::from_error(err).map_into_body(),
-        };
-
-        let mut res = self.responder.respond_to(req);
-
-        if let Some(status) = self.status {
-            *res.status_mut() = status;
-        }
-
-        for (k, v) in headers {
-            // TODO: before v4, decide if this should be append instead
-            res.headers_mut().insert(k, v);
-        }
-
-        res
-    }
-}
-
 #[cfg(test)]
 pub(crate) mod tests {
    use actix_service::Service;
@@ -455,59 +342,4 @@ pub(crate) mod tests {

        assert_eq!(res.status(), StatusCode::BAD_REQUEST);
    }
-
-    #[actix_rt::test]
-    async fn test_custom_responder() {
-        let req = TestRequest::default().to_http_request();
-        let res = "test"
-            .to_string()
-            .with_status(StatusCode::BAD_REQUEST)
-            .respond_to(&req);
-
-        assert_eq!(res.status(), StatusCode::BAD_REQUEST);
-        assert_eq!(
-            to_bytes(res.into_body()).await.unwrap(),
-            Bytes::from_static(b"test"),
-        );
-
-        let res = "test"
-            .to_string()
-            .with_header(("content-type", "json"))
-            .respond_to(&req);
-
-        assert_eq!(res.status(), StatusCode::OK);
-        assert_eq!(
-            res.headers().get(CONTENT_TYPE).unwrap(),
-            HeaderValue::from_static("json")
-        );
-        assert_eq!(
-            to_bytes(res.into_body()).await.unwrap(),
-            Bytes::from_static(b"test"),
-        );
-    }
-
-    #[actix_rt::test]
-    async fn test_tuple_responder_with_status_code() {
-        let req = TestRequest::default().to_http_request();
-        let res = ("test".to_string(), StatusCode::BAD_REQUEST).respond_to(&req);
-        assert_eq!(res.status(), StatusCode::BAD_REQUEST);
-        assert_eq!(
-            to_bytes(res.into_body()).await.unwrap(),
-            Bytes::from_static(b"test"),
-        );
-
-        let req = TestRequest::default().to_http_request();
-        let res = ("test".to_string(), StatusCode::OK)
-            .with_header((CONTENT_TYPE, mime::APPLICATION_JSON))
-            .respond_to(&req);
-        assert_eq!(res.status(), StatusCode::OK);
-        assert_eq!(
-            res.headers().get(CONTENT_TYPE).unwrap(),
-            HeaderValue::from_static("application/json")
-        );
-        assert_eq!(
-            to_bytes(res.into_body()).await.unwrap(),
-            Bytes::from_static(b"test"),
-        );
-    }
 }
--- a/src/response/response.rs
+++ b/src/response/response.rs
@@ -8,7 +8,7 @@ use std::{
 };

 use actix_http::{
-    body::{BoxBody, MessageBody, None as NoneBody},
+    body::{BoxBody, EitherBody, MessageBody},
    header::HeaderMap,
    Extensions, Response, ResponseHead, StatusCode,
 };
@@ -22,11 +22,11 @@ use {
    cookie::Cookie,
 };

-use crate::{any_body::AnyBody, error::Error, HttpResponseBuilder};
+use crate::{error::Error, HttpResponseBuilder};

 /// An outgoing response.
 pub struct HttpResponse<B = BoxBody> {
-    res: Response<AnyBody<B>>,
+    res: Response<B>,
    pub(crate) error: Option<Error>,
 }

@@ -35,7 +35,7 @@ impl HttpResponse<BoxBody> {
    #[inline]
    pub fn new(status: StatusCode) -> Self {
        Self {
-            res: Response::with_body(status, AnyBody::default()),
+            res: Response::new(status),
            error: None,
        }
    }
@@ -54,13 +54,6 @@ impl HttpResponse<BoxBody> {
        response.error = Some(error);
        response
    }
-
-    pub fn map_into_body<B>(self) -> HttpResponse<B>
-    where
-        B: MessageBody + 'static,
-    {
-        self.map_body(|_, body| body.into_body())
-    }
 }

 impl<B> HttpResponse<B> {
@@ -68,7 +61,7 @@ impl<B> HttpResponse<B> {
    #[inline]
    pub fn with_body(status: StatusCode, body: B) -> Self {
        Self {
-            res: Response::with_body(status, AnyBody::Stream { body }),
+            res: Response::with_body(status, body),
            error: None,
        }
    }
@@ -189,12 +182,12 @@ impl<B> HttpResponse<B> {

    /// Get body of this response
    #[inline]
-    pub fn body(&self) -> &AnyBody<B> {
+    pub fn body(&self) -> &B {
        self.res.body()
    }

    /// Set a body
-    pub fn set_body<B2>(self, body: AnyBody<B2>) -> HttpResponse<B2> {
+    pub fn set_body<B2>(self, body: B2) -> HttpResponse<B2> {
        HttpResponse {
            res: self.res.set_body(body),
            error: None,
@@ -203,12 +196,12 @@ impl<B> HttpResponse<B> {
    }

    /// Split response and body
-    pub fn into_parts(self) -> (HttpResponse<()>, AnyBody<B>) {
+    pub fn into_parts(self) -> (HttpResponse<()>, B) {
        let (head, body) = self.res.into_parts();

        (
            HttpResponse {
-                res: head.map_body(|_, _b| AnyBody::default()),
+                res: head,
                error: None,
            },
            body,
@@ -218,7 +211,7 @@ impl<B> HttpResponse<B> {
    /// Drop request's body
    pub fn drop_body(self) -> HttpResponse<()> {
        HttpResponse {
-            res: self.res.drop_body().map_body(|_, _b| AnyBody::default()),
+            res: self.res.drop_body(),
            error: None,
        }
    }
@@ -226,7 +219,7 @@ impl<B> HttpResponse<B> {
    /// Set a body and return previous body value
    pub fn map_body<F, B2>(self, f: F) -> HttpResponse<B2>
    where
-        F: FnOnce(&mut ResponseHead, AnyBody<B>) -> AnyBody<B2>,
+        F: FnOnce(&mut ResponseHead, B) -> B2,
    {
        HttpResponse {
            res: self.res.map_body(f),
@@ -236,28 +229,27 @@ impl<B> HttpResponse<B> {

    // TODO: docs for the body map methods below

+    #[inline]
+    pub fn map_into_left_body<R>(self) -> HttpResponse<EitherBody<B, R>> {
+        self.map_body(|_, body| EitherBody::left(body))
+    }
+
+    #[inline]
+    pub fn map_into_right_body<L>(self) -> HttpResponse<EitherBody<L, B>> {
+        self.map_body(|_, body| EitherBody::right(body))
+    }
+
    #[inline]
    pub fn map_into_boxed_body(self) -> HttpResponse<BoxBody>
    where
        B: MessageBody + 'static,
    {
-        self.map_body(|_, body| AnyBody::Boxed {
-            body: match body {
-                AnyBody::None => BoxBody::new(NoneBody::new()),
-                AnyBody::Full { body } => BoxBody::new(body),
-                AnyBody::Stream { body } => BoxBody::new(body),
-                AnyBody::Boxed { body } => body,
-            },
-        })
+        // TODO: avoid double boxing with down-casting, if it improves perf
+        self.map_body(|_, body| BoxBody::new(body))
    }

    /// Extract response body
-    pub fn take_body(&mut self) -> AnyBody<B> {
-        self.res.take_body()
-    }
-
-    /// Extract response body
-    pub fn into_body(self) -> AnyBody<B> {
+    pub fn into_body(self) -> B {
        self.res.into_body()
    }
 }
@@ -274,8 +266,8 @@ where
    }
 }

-impl<B> From<Response<AnyBody<B>>> for HttpResponse<B> {
-    fn from(res: Response<AnyBody<B>>) -> Self {
+impl<B> From<Response<B>> for HttpResponse<B> {
+    fn from(res: Response<B>) -> Self {
        HttpResponse { res, error: None }
    }
 }
@@ -286,7 +278,7 @@ impl From<Error> for HttpResponse {
    }
 }

-impl<B> From<HttpResponse<B>> for Response<AnyBody<B>> {
+impl<B> From<HttpResponse<B>> for Response<B> {
    fn from(res: HttpResponse<B>) -> Self {
        // this impl will always be called as part of dispatcher

@@ -299,14 +291,14 @@ impl<B> From<HttpResponse<B>> for Response<AnyBody<B>> {
    }
 }

-// Future is only implemented for default payload type because it's the most useful for making
+// Future is only implemented for BoxBody payload type because it's the most useful for making
 // simple handlers without async blocks. Making it generic over all MessageBody types requires a
 // future impl on Response which would cause it's body field to be, undesirably, Option<B>.
 //
 // This impl is not particularly efficient due to the Response construction and should probably
 // not be invoked if performance is important. Prefer an async fn/block in such cases.
-impl Future for HttpResponse {
-    type Output = Result<Response<AnyBody>, Error>;
+impl Future for HttpResponse<BoxBody> {
+    type Output = Result<Response<BoxBody>, Error>;

    fn poll(mut self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<Self::Output> {
        if let Some(err) = self.error.take() {
@@ -315,7 +307,7 @@ impl Future for HttpResponse {

        Poll::Ready(Ok(mem::replace(
            &mut self.res,
-            Response::with_body(StatusCode::default(), AnyBody::None),
+            Response::new(StatusCode::default()),
        )))
    }
 }
--- a/src/scope.rs
+++ b/src/scope.rs
@@ -935,7 +935,7 @@ mod tests {
                web::scope("app")
                    .wrap(
                        DefaultHeaders::new()
-                            .header(header::CONTENT_TYPE, HeaderValue::from_static("0001")),
+                            .add((header::CONTENT_TYPE, HeaderValue::from_static("0001"))),
                    )
                    .service(web::resource("/test").route(web::get().to(HttpResponse::Ok))),
            ),
--- a/src/server.rs
+++ b/src/server.rs
@@ -17,7 +17,7 @@ use actix_tls::accept::openssl::reexports::{AlpnError, SslAcceptor, SslAcceptorB
 #[cfg(feature = "rustls")]
 use actix_tls::accept::rustls::reexports::ServerConfig as RustlsServerConfig;

-use crate::{any_body::AnyBody, config::AppConfig, Error};
+use crate::{config::AppConfig, Error};

 struct Socket {
    scheme: &'static str,
@@ -55,7 +55,7 @@ where
    S: ServiceFactory<Request, Config = AppConfig>,
    S::Error: Into<Error>,
    S::InitError: fmt::Debug,
-    S::Response: Into<Response<AnyBody<B>>>,
+    S::Response: Into<Response<B>>,
    B: MessageBody,
 {
    pub(super) factory: F,
@@ -75,7 +75,7 @@ where
    S: ServiceFactory<Request, Config = AppConfig> + 'static,
    S::Error: Into<Error> + 'static,
    S::InitError: fmt::Debug,
-    S::Response: Into<Response<AnyBody<B>>> + 'static,
+    S::Response: Into<Response<B>> + 'static,
    <S::Service as Service<Request>>::Future: 'static,
    S::Service: 'static,

@@ -300,10 +300,9 @@ where
                        })
                    };

-                    let fac = factory().into_factory().map_err(|err| {
-                        let res: actix_http::Response<_> = err.into().error_response().into();
-                        res.map_into_boxed_body()
-                    });
+                    let fac = factory()
+                        .into_factory()
+                        .map_err(|err| err.into().error_response());

                    svc.finish(map_config(fac, move |_| {
                        AppConfig::new(false, host.clone(), addr)
@@ -361,10 +360,9 @@ where
                        svc
                    };

-                    let fac = factory().into_factory().map_err(|err| {
-                        let res: actix_http::Response<_> = err.into().error_response().into();
-                        res.map_into_boxed_body()
-                    });
+                    let fac = factory()
+                        .into_factory()
+                        .map_err(|err| err.into().error_response());

                    svc.finish(map_config(fac, move |_| {
                        AppConfig::new(true, host.clone(), addr)
@@ -546,10 +544,9 @@ where
                        .on_connect_ext(move |io: &_, ext: _| (&*handler)(io as &dyn Any, ext));
                }

-                let fac = factory().into_factory().map_err(|err| {
-                    let res: actix_http::Response<_> = err.into().error_response().into();
-                    res.map_into_boxed_body()
-                });
+                let fac = factory()
+                    .into_factory()
+                    .map_err(|err| err.into().error_response());

                svc.finish(map_config(fac, move |_| config.clone()))
            })
@@ -588,10 +585,9 @@ where
                    socket_addr,
                );

-                let fac = factory().into_factory().map_err(|err| {
-                    let res: actix_http::Response<_> = err.into().error_response().into();
-                    res.map_into_boxed_body()
-                });
+                let fac = factory()
+                    .into_factory()
+                    .map_err(|err| err.into().error_response());

                fn_service(|io: UnixStream| async { Ok((io, Protocol::Http1, None)) }).and_then(
                    HttpService::build()
@@ -614,7 +610,7 @@ where
    S: ServiceFactory<Request, Config = AppConfig>,
    S::Error: Into<Error>,
    S::InitError: fmt::Debug,
-    S::Response: Into<Response<AnyBody<B>>>,
+    S::Response: Into<Response<B>>,
    S::Service: 'static,
    B: MessageBody,
 {
--- a/src/service.rs
+++ b/src/service.rs
@@ -5,7 +5,7 @@ use std::{
 };

 use actix_http::{
-    body::{self, BoxBody, MessageBody},
+    body::{BoxBody, EitherBody, MessageBody},
    header::HeaderMap,
    Extensions, HttpMessage, Method, Payload, PayloadStream, RequestHead, Response,
    ResponseHead, StatusCode, Uri, Version,
@@ -19,7 +19,6 @@ use actix_service::{
 use cookie::{Cookie, ParseError as CookieParseError};

 use crate::{
-    any_body::AnyBody,
    config::{AppConfig, AppService},
    dev::ensure_leading_slash,
    guard::Guard,
@@ -113,7 +112,7 @@ impl ServiceRequest {

    /// Create service response
    #[inline]
-    pub fn into_response<B, R: Into<Response<AnyBody<B>>>>(self, res: R) -> ServiceResponse<B> {
+    pub fn into_response<B, R: Into<Response<B>>>(self, res: R) -> ServiceResponse<B> {
        let res = HttpResponse::from(res.into());
        ServiceResponse::new(self.req, res)
    }
@@ -411,14 +410,15 @@ impl<B> ServiceResponse<B> {
        self.response.headers_mut()
    }

+    /// Destructures `ServiceResponse` into request and response components.
    #[inline]
-    pub fn take_body(&mut self) -> AnyBody<B> {
-        self.response.take_body()
+    pub fn into_parts(self) -> (HttpRequest, HttpResponse<B>) {
+        (self.request, self.response)
    }

    /// Extract response body
    #[inline]
-    pub fn into_body(self) -> AnyBody<B> {
+    pub fn into_body(self) -> B {
        self.response.into_body()
    }

@@ -426,7 +426,7 @@ impl<B> ServiceResponse<B> {
    #[inline]
    pub fn map_body<F, B2>(self, f: F) -> ServiceResponse<B2>
    where
-        F: FnOnce(&mut ResponseHead, AnyBody<B>) -> AnyBody<B2>,
+        F: FnOnce(&mut ResponseHead, B) -> B2,
    {
        let response = self.response.map_body(f);

@@ -436,29 +436,22 @@ impl<B> ServiceResponse<B> {
        }
    }

-    // #[inline]
-    // pub fn map_into_left_body<R>(self) -> ServiceResponse<EitherBody<B, R>> {
-    //     self.map_body(|_, body| EitherBody::left(body))
-    // }
+    #[inline]
+    pub fn map_into_left_body<R>(self) -> ServiceResponse<EitherBody<B, R>> {
+        self.map_body(|_, body| EitherBody::left(body))
+    }

-    // #[inline]
-    // pub fn map_into_right_body<L>(self) -> ServiceResponse<EitherBody<L, B>> {
-    //     self.map_body(|_, body| EitherBody::right(body))
-    // }
+    #[inline]
+    pub fn map_into_right_body<L>(self) -> ServiceResponse<EitherBody<L, B>> {
+        self.map_body(|_, body| EitherBody::right(body))
+    }

    #[inline]
    pub fn map_into_boxed_body(self) -> ServiceResponse<BoxBody>
    where
        B: MessageBody + 'static,
    {
-        self.map_body(|_, body| AnyBody::Stream {
-            body: match body {
-                AnyBody::None => BoxBody::new(body::None::new()),
-                AnyBody::Full { body } => BoxBody::new(body),
-                AnyBody::Stream { body } => BoxBody::new(body),
-                AnyBody::Boxed { body } => body,
-            },
-        })
+        self.map_body(|_, body| BoxBody::new(body))
    }
 }

@@ -468,8 +461,8 @@ impl<B> From<ServiceResponse<B>> for HttpResponse<B> {
    }
 }

-impl<B> From<ServiceResponse<B>> for Response<AnyBody<B>> {
-    fn from(res: ServiceResponse<B>) -> Response<AnyBody<B>> {
+impl<B> From<ServiceResponse<B>> for Response<B> {
+    fn from(res: ServiceResponse<B>) -> Response<B> {
        res.response.into()
    }
 }
--- a/src/test.rs
+++ b/src/test.rs
@@ -4,8 +4,8 @@ use std::{borrow::Cow, net::SocketAddr, rc::Rc};

 pub use actix_http::test::TestBuffer;
 use actix_http::{
-    header::IntoHeaderPair, test::TestRequest as HttpTestRequest, Extensions, Method, Request,
-    StatusCode, Uri, Version,
+    header::TryIntoHeaderPair, test::TestRequest as HttpTestRequest, Extensions, Method,
+    Request, StatusCode, Uri, Version,
 };
 use actix_router::{Path, ResourceDef, Url};
 use actix_service::{IntoService, IntoServiceFactory, Service, ServiceFactory};
@@ -163,7 +163,7 @@ where

    actix_rt::pin!(body);
    while let Some(item) = poll_fn(|cx| body.as_mut().poll_next(cx)).await {
-        bytes.extend_from_slice(&item.unwrap());
+        bytes.extend_from_slice(&item.map_err(Into::into).unwrap());
    }

    bytes.freeze()
@@ -205,7 +205,7 @@ where

    actix_rt::pin!(body);
    while let Some(item) = poll_fn(|cx| body.as_mut().poll_next(cx)).await {
-        bytes.extend_from_slice(&item.unwrap());
+        bytes.extend_from_slice(&item.map_err(Into::into).unwrap());
    }

    bytes.freeze()
@@ -445,19 +445,13 @@ impl TestRequest {
    }

    /// Insert a header, replacing any that were set with an equivalent field name.
-    pub fn insert_header<H>(mut self, header: H) -> Self
-    where
-        H: IntoHeaderPair,
-    {
+    pub fn insert_header(mut self, header: impl TryIntoHeaderPair) -> Self {
        self.req.insert_header(header);
        self
    }

    /// Append a header, keeping any that were set with an equivalent field name.
-    pub fn append_header<H>(mut self, header: H) -> Self
-    where
-        H: IntoHeaderPair,
-    {
+    pub fn append_header(mut self, header: impl TryIntoHeaderPair) -> Self {
        self.req.append_header(header);
        self
    }
--- a/Show More
+++ b/Show More
Author	SHA1	Message	Date
Rob Ede	2ee953a118	remove either crate conversions	2021-12-14 19:01:14 +00:00
Rob Ede	fb091b2b88	split up router pattern and resource_path modules	2021-12-14 18:59:59 +00:00
Rob Ede	11ee8ec3ab	align remaining header map terminology (#2510 )	2021-12-13 16:08:08 +00:00
Rob Ede	551a0d973c	doc tweaks	2021-12-13 02:58:19 +00:00
Rob Ede	cea44be670	add test for returning App from function	2021-12-11 16:18:28 +00:00
Rob Ede	b41b346c00	inline trivial body methods	2021-12-11 16:05:08 +00:00
Rob Ede	5b0a50249b	prepare actix-multipart release 0.4.0-beta.10	2021-12-11 00:35:26 +00:00
Rob Ede	60b030ff53	prepare actix-web-actors release 4.0.0-beta.8	2021-12-11 00:34:23 +00:00
Rob Ede	fc4e9ff96b	prepare actix-web-codegen release 0.5.0-beta.6	2021-12-11 00:33:31 +00:00
Rob Ede	6481a5fb73	prepare actix-test release 0.1.0-beta.8	2021-12-11 00:32:26 +00:00
Rob Ede	0cd7c17682	prepare actix-http-test release 3.0.0-beta.9	2021-12-11 00:32:00 +00:00
Rob Ede	ed2f5b40b9	prepare actix-files release 0.6.0-beta.10	2021-12-11 00:31:41 +00:00
Rob Ede	cc37be9700	prepare actix-web release 4.0.0-beta.14	2021-12-11 00:30:12 +00:00
Rob Ede	e1cdabe5cb	prepare awc release 3.0.0-beta.13	2021-12-11 00:28:38 +00:00
Rob Ede	d0f4c809ca	prepare actix-http release 3.0.0-beta.15	2021-12-11 00:22:09 +00:00
Rob Ede	65dd5dfa7b	bump script updates referenced crate versions	2021-12-11 00:21:30 +00:00
Rob Ede	f62383a975	unpin h2	2021-12-10 22:13:12 +00:00
Ali MJ Al-Nasrawy	f9348d7129	add ServiceResponse::into_parts (#2499 )	2021-12-09 14:57:27 +00:00
Rob Ede	774ac7fec4	provide optimisation path for single-chunk body types (#2497 )	2021-12-09 13:52:35 +00:00
Rob Ede	69fa17f66f	clean future h2 dispatcher	2021-12-09 11:27:29 +00:00
Rob Ede	816d68dee8	pin h2 temporarily	2021-12-09 00:46:28 +00:00
Rob Ede	7dc034f0fb	Remove extensions from head (#2487 )	2021-12-08 22:58:50 +00:00