refactor: remove async_await feature gate

`async_await` is stabilized in rust-lang/rust#63209.
This commit fixes `hyper` build with latest nightly compiler.

benches/end_to_end.rs

@@ -1,4 +1,3 @@
-#![feature(async_await)]
 #![feature(test)]
 #![deny(warnings)]
 

benches/pipeline.rs

@@ -1,4 +1,3 @@
-#![feature(async_await)]
 #![feature(test)]
 #![deny(warnings)]
 

benches/server.rs

@@ -1,4 +1,3 @@
-#![feature(async_await)]
 #![feature(test)]
 #![deny(warnings)]
 

examples/client.rs

@@ -1,4 +1,3 @@
-#![feature(async_await)]
 #![deny(warnings)]
 extern crate hyper;
 extern crate pretty_env_logger;

examples/client_json.rs

@@ -1,4 +1,3 @@
-#![feature(async_await)]
 #![deny(warnings)]
 extern crate hyper;
 #[macro_use]

examples/echo.rs

@@ -1,4 +1,3 @@
-#![feature(async_await)]
 //#![deny(warnings)]
 
 use hyper::{Body, Method, Request, Response, Server, StatusCode};

examples/hello.rs

@@ -1,4 +1,3 @@
-#![feature(async_await)]
 #![deny(warnings)]
 
 use hyper::{Body, Request, Response, Server};

examples/multi_server.rs

@@ -1,4 +1,3 @@
-#![feature(async_await)]
 #![deny(warnings)]
 extern crate hyper;
 extern crate pretty_env_logger;

examples/params.rs

@@ -1,4 +1,3 @@
-#![feature(async_await)]
 // #![deny(warnings)]  // FIXME: https://github.com/rust-lang/rust/issues/62411
 extern crate hyper;
 extern crate pretty_env_logger;

examples/proxy.rs

@@ -1,4 +1,3 @@
-#![feature(async_await)]
 #![deny(warnings)]
 
 use hyper::{Client, Error, Server};

examples/send_file.rs

@@ -1,4 +1,3 @@
-#![feature(async_await)]
 #![deny(warnings)]
 
 use tokio::io::AsyncReadExt;

examples/single_threaded.rs

@@ -1,4 +1,3 @@
-#![feature(async_await)]
 #![deny(warnings)]
 
 use std::cell::Cell;

examples/state.rs

@@ -1,4 +1,3 @@
-#![feature(async_await)]
 #![deny(warnings)]
 
 use std::sync::{Arc, atomic::{AtomicUsize, Ordering}};

examples/tower_server.rs

@@ -1,4 +1,3 @@
-#![feature(async_await)]
 #![deny(warnings)]
 
 use hyper::{Body, Request, Response, Server};

examples/upgrades.rs

@@ -1,4 +1,3 @@
-#![feature(async_await)]
 #![deny(warnings)]
 
 // Note: `hyper::upgrade` docs link to this upgrade.

examples/web_api.rs

@@ -1,4 +1,3 @@
-#![feature(async_await)]
 #![deny(warnings)]
 
 use hyper::{Body, Chunk, Client, Method, Request, Response, Server, StatusCode, header};

src/client/conn.rs

@@ -182,7 +182,6 @@ where
     /// # Example
     ///
     /// ```
-    /// # #![feature(async_await)]
     /// # use http::header::HOST;
     /// # use hyper::client::conn::SendRequest;
     /// # use hyper::Body;

src/client/connect/http.rs

@@ -46,7 +46,6 @@ pub struct HttpConnector<R = GaiResolver> {
 /// # Example
 ///
 /// ```
-/// # #![feature(async_await)]
 /// # async fn doc() -> hyper::Result<()> {
 /// use hyper::Uri;
 /// use hyper::client::{Client, connect::HttpInfo};

src/client/mod.rs

@@ -27,7 +27,6 @@
 //! [full client example](https://github.com/hyperium/hyper/blob/master/examples/client.rs).
 //!
 //! ```
-//! # #![feature(async_await)]
 //! use hyper::{Client, Uri};
 //!
 //! # #[cfg(feature = "runtime")]

src/lib.rs

@@ -4,7 +4,6 @@
 // XXX NOOOOOOOO
 //#![cfg_attr(test, deny(warnings))]
 #![allow(warnings)]
-#![feature(async_await)]
 #![cfg_attr(all(test, feature = "nightly"), feature(test))]
 
 //! # hyper

src/server/conn.rs

@@ -331,7 +331,6 @@ impl<E> Http<E> {
     /// # Example
     ///
     /// ```
-    /// # #![feature(async_await)]
     /// # use hyper::{Body, Request, Response};
     /// # use hyper::service::Service;
     /// # use hyper::server::conn::Http;

src/server/mod.rs

@@ -19,7 +19,6 @@
 //! ## Example
 //!
 //! ```no_run
-//! # #![feature(async_await)]
 //! use hyper::{Body, Error, Response, Server};
 //! use hyper::service::{make_service_fn, service_fn};
 //!
@@ -164,7 +163,6 @@ where
     /// # Example
     ///
     /// ```
-    /// # #![feature(async_await)]
     /// # fn main() {}
     /// # #[cfg(feature = "runtime")]
     /// # async fn run() {
@@ -360,7 +358,6 @@ impl<I, E> Builder<I, E> {
     /// # Example
     ///
     /// ```
-    /// # #![feature(async_await)]
     /// # #[cfg(not(feature = "runtime"))]
     /// # fn main() {}
     /// # #[cfg(feature = "runtime")]

src/service/make_service.rs

@@ -133,7 +133,6 @@ where
 /// # Example
 ///
 /// ```rust,no_run
-/// # #![feature(async_await)]
 /// # #[cfg(feature = "runtime")]
 /// # #[tokio::main]
 /// # async fn main() {

src/service/service.rs

@@ -70,7 +70,6 @@ mod sealed {
 /// # Example
 ///
 /// ```rust
-/// # #![feature(async_await)]
 /// use hyper::{Body, Request, Response, Version};
 /// use hyper::service::service_fn;
 ///

tests/client.rs

@@ -1,4 +1,3 @@
-#![feature(async_await)]
 #![deny(warnings)]
 extern crate bytes;
 extern crate hyper;

tests/server.rs

@@ -1,4 +1,4 @@
-#![feature(async_await, async_closure)]
+#![feature(async_closure)]
 #![deny(warnings)]
 extern crate http;
 extern crate hyper;