diff --git a/actix-http/CHANGES.md b/actix-http/CHANGES.md
index 48c730bb2..b2e5af79f 100644
--- a/actix-http/CHANGES.md
+++ b/actix-http/CHANGES.md
@@ -2,6 +2,10 @@
 
 ## Unreleased
 
+### Added
+
+- Implement `FromIterator<(HeaderName, HeaderValue)>` for `HeaderMap`.
+
 ## 3.8.0
 
 ### Added
diff --git a/actix-http/src/header/map.rs b/actix-http/src/header/map.rs
index b86798a4c..6da01d2c0 100644
--- a/actix-http/src/header/map.rs
+++ b/actix-http/src/header/map.rs
@@ -13,8 +13,9 @@ use super::AsHeaderName;
 /// `HeaderMap` is a "multi-map" of [`HeaderName`] to one or more [`HeaderValue`]s.
 ///
 /// # Examples
+///
 /// ```
-/// use actix_http::header::{self, HeaderMap, HeaderValue};
+/// # use actix_http::header::{self, HeaderMap, HeaderValue};
 ///
 /// let mut map = HeaderMap::new();
 ///
@@ -29,6 +30,21 @@ use super::AsHeaderName;
 ///
 /// assert!(!map.contains_key(header::ORIGIN));
 /// ```
+///
+/// Construct a header map using the [`FromIterator`] implementation. Note that it uses the append
+/// strategy, so duplicate header names are preserved.
+///
+/// ```
+/// use actix_http::header::{self, HeaderMap, HeaderValue};
+///
+/// let headers = HeaderMap::from_iter([
+///     (header::CONTENT_TYPE, HeaderValue::from_static("text/plain")),
+///     (header::COOKIE, HeaderValue::from_static("foo=1")),
+///     (header::COOKIE, HeaderValue::from_static("bar=1")),
+/// ]);
+///
+/// assert_eq!(headers.len(), 3);
+/// ```
 #[derive(Debug, Clone, Default)]
 pub struct HeaderMap {
     pub(crate) inner: AHashMap<HeaderName, Value>,
@@ -368,8 +384,8 @@ impl HeaderMap {
     /// let removed = map.insert(header::ACCEPT, HeaderValue::from_static("text/html"));
     /// assert!(!removed.is_empty());
     /// ```
-    pub fn insert(&mut self, key: HeaderName, val: HeaderValue) -> Removed {
-        let value = self.inner.insert(key, Value::one(val));
+    pub fn insert(&mut self, name: HeaderName, val: HeaderValue) -> Removed {
+        let value = self.inner.insert(name, Value::one(val));
         Removed::new(value)
     }
 
@@ -636,6 +652,16 @@ impl<'a> IntoIterator for &'a HeaderMap {
     }
 }
 
+impl FromIterator<(HeaderName, HeaderValue)> for HeaderMap {
+    fn from_iter<T: IntoIterator<Item = (HeaderName, HeaderValue)>>(iter: T) -> Self {
+        iter.into_iter()
+            .fold(Self::new(), |mut map, (name, value)| {
+                map.append(name, value);
+                map
+            })
+    }
+}
+
 /// Convert a `http::HeaderMap` to our `HeaderMap`.
 impl From<http::HeaderMap> for HeaderMap {
     fn from(mut map: http::HeaderMap) -> Self {
diff --git a/awc/src/any_body.rs b/awc/src/any_body.rs
index 08f5cc25e..ef0edfb9e 100644
--- a/awc/src/any_body.rs
+++ b/awc/src/any_body.rs
@@ -163,6 +163,7 @@ mod tests {
 
     use super::*;
 
+    #[allow(dead_code)]
     struct PinType(PhantomPinned);
 
     impl MessageBody for PinType {