message: docs(server): update `with_graceful_shutdown doc test
diff: @@ -164,34 +164,32 @@ where
  /// # Example
  ///
  /// ```
  - /// # extern crate hyper;
  - /// # extern crate futures;
  - /// # use futures::Future;
  + /// # #![feature(async_await)]
  /// # fn main() {}
  /// # #[cfg(feature = "runtime")]
  - /// # fn run() {
  - /// # use hyper::{Body, Response, Server};
  - /// # use hyper::service::service_fn_ok;
  - /// # let new_service = || {
  - /// # service_fn_ok(|_req| {
  - /// # Response::new(Body::from("Hello World"))
  - /// # })
  - /// # };
  - ///
  + /// # async fn run() {
  + /// # use hyper::{Body, Response, Server, Error};
  + /// # use hyper::service::{make_service_fn, service_fn};
  + /// # let make_service = make_service_fn(|_| async {
  + /// # Ok::<_, Error>(service_fn(|_req| async {
  + /// # Ok::<_, Error>(Response::new(Body::from("Hello World")))
  + /// # }))
  + /// # });
  /// // Make a server from the previous examples...
  /// let server = Server::bind(&([127, 0, 0, 1], 3000).into())
  - /// .serve(new_service);
  - ///
  - /// // Prepare some signal for when the server should start
  - /// // shutting down...
  - /// let (tx, rx) = futures::sync::oneshot::channel::<()>();
  + /// .serve(make_service);
  ///
  + /// // Prepare some signal for when the server should start shutting down...
  + /// let (tx, rx) = tokio::sync::oneshot::channel::<()>();
  /// let graceful = server
  - /// .with_graceful_shutdown(rx)
  - /// .map_err(|err| eprintln!("server error: {}", err));
  + /// .with_graceful_shutdown(async {
  + /// rx.await.ok();
  + /// });
  ///
  - /// // Spawn `server` onto an Executor...
  - /// hyper::rt::spawn(graceful);
  + /// // Await the `server` receiving the signal...
  + /// if let Err(e) = graceful.await {
  + /// eprintln!("server error: {}", e);
  + /// }
  ///
  /// // And later, trigger the signal by calling `tx.send(())`.
  /// let _ = tx.send(());
  