Implement IntoResponse for http::response::Parts (#490)

* Implement `IntoResponse` for `http::response::Parts`

Not sure there are many use cases for this but still thinks it makes to
provide since other crates can't.

* Use `Response::from_parts`

axum/CHANGELOG.md

@@ -7,7 +7,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 # Unreleased
 
-- None
+- Implement `IntoResponse` for `http::response::Parts` ([#490])
+
+[#490]: https://github.com/tokio-rs/axum/pull/490
 
 # 0.3.2 (08. November, 2021)
 

axum/src/response/mod.rs

@@ -245,6 +245,15 @@ impl_into_response_for_body!(hyper::Body);
 impl_into_response_for_body!(Full<Bytes>);
 impl_into_response_for_body!(Empty<Bytes>);
 
+impl IntoResponse for http::response::Parts {
+    type Body = Empty<Bytes>;
+    type BodyError = Infallible;
+
+    fn into_response(self) -> Response<Self::Body> {
+        Response::from_parts(self, Empty::new())
+    }
+}
+
 impl<E> IntoResponse for http_body::combinators::BoxBody<Bytes, E>
 where
     E: Into<BoxError> + 'static,