update readme

README.md

@@ -13,7 +13,7 @@ Actix web is licensed under the [Apache-2.0 license](http://opensource.org/licen
 
 ## Features
 
-  * HTTP/1 and HTTP/2
+  * Supported HTTP/1 and HTTP/2 protocols
   * Streaming and pipelining
   * Keep-alive and slow requests handling
   * [WebSockets](https://actix.github.io/actix-web/actix_web/ws/index.html)
@@ -32,21 +32,24 @@ actix-web = { git = "https://github.com/actix/actix-web" }
 
 ## HTTP/2
 
-### Usage
-
 Actix web automatically upgrades connection to `http/2` if possible.
 
 ### Negotiation
 
-To use http/2 protocol over tls without prior knowlage requires 
+To use `http/2` protocol over tls without prior knowlage requires
 [tls alpn](https://tools.ietf.org/html/rfc7301). At the moment only
-rust-openssl supports alpn.
+`rust-openssl` supports alpn.
 
 ```toml
 [dependencies]
 actix-web = { git = "https://github.com/actix/actix-web", features=["alpn"] }
 ```
 
+Upgrade to `http/2` schema described in
+[rfc section3.2](https://http2.github.io/http2-spec/#rfc.section.3.2) is not supported.
+Starting `http/2` with prior knowledge is supported for both clear text connection
+and tls connection. [rfc link](https://http2.github.io/http2-spec/#rfc.section.3.4)
+
 ## Example
 
 * [Basic](https://github.com/actix/actix-web/tree/master/examples/basic.rs)

src/channel.rs

@@ -72,7 +72,7 @@ impl<T, A, H> Future for HttpChannel<T, A, H>
                 match h1.poll() {
                     Ok(Async::Ready(h1::Http1Result::Done)) =>
                         return Ok(Async::Ready(())),
-                    Ok(Async::Ready(h1::Http1Result::Upgrade)) => (),
+                    Ok(Async::Ready(h1::Http1Result::Switch)) => (),
                     Ok(Async::NotReady) =>
                         return Ok(Async::NotReady),
                     Err(_) =>

src/h1.rs

@@ -31,7 +31,7 @@ const HTTP2_PREFACE: [u8; 14] = *b"PRI * HTTP/2.0";
 
 pub(crate) enum Http1Result {
     Done,
-    Upgrade,
+    Switch,
 }
 
 pub(crate) struct Http1<T: AsyncWrite + 'static, A: 'static, H: 'static> {
@@ -157,7 +157,7 @@ impl<T, A, H> Http1<T, A, H>
             // no keep-alive
             if !self.keepalive && self.tasks.is_empty() {
                 if self.h2 {
-                    return Ok(Async::Ready(Http1Result::Upgrade))
+                    return Ok(Async::Ready(Http1Result::Switch))
                 } else {
                     return Ok(Async::Ready(Http1Result::Done))
                 }