feat(lib): update to std::future::Future

BREAKING CHANGE: All usage of async traits (`Future`, `Stream`,
`AsyncRead`, `AsyncWrite`, etc) are updated to newer versions.

examples/client.rs

@@ -1,3 +1,4 @@
+#![feature(async_await)]
 #![deny(warnings)]
 extern crate hyper;
 extern crate pretty_env_logger;
@@ -6,7 +7,7 @@ use std::env;
 use std::io::{self, Write};
 
 use hyper::Client;
-use hyper::rt::{self, Future, Stream};
+use hyper::rt;
 
 fn main() {
     pretty_env_logger::init();
@@ -35,31 +36,34 @@ fn main() {
     rt::run(fetch_url(url));
 }
 
-fn fetch_url(url: hyper::Uri) -> impl Future<Item=(), Error=()> {
+async fn fetch_url(url: hyper::Uri) {
     let client = Client::new();
 
-    client
-        // Fetch the url...
-        .get(url)
-        // And then, if we get a response back...
-        .and_then(|res| {
-            println!("Response: {}", res.status());
-            println!("Headers: {:#?}", res.headers());
+    let res = match client.get(url).await {
+        Ok(res) => res,
+        Err(err) => {
+            eprintln!("Response Error: {}", err);
+            return;
+        }
+    };
 
-            // The body is a stream, and for_each returns a new Future
-            // when the stream is finished, and calls the closure on
-            // each chunk of the body...
-            res.into_body().for_each(|chunk| {
+    println!("Response: {}", res.status());
+    println!("Headers: {:#?}\n", res.headers());
+
+    let mut body = res.into_body();
+
+    while let Some(next) = body.next().await {
+        match next {
+            Ok(chunk) => {
                 io::stdout().write_all(&chunk)
-                    .map_err(|e| panic!("example expects stdout is open, error={}", e))
-            })
-        })
-        // If all good, just tell the user...
-        .map(|_| {
-            println!("\n\nDone.");
-        })
-        // If there was an error, let the user know...
-        .map_err(|err| {
-            eprintln!("Error {}", err);
-        })
+                    .expect("example expects stdout is open");
+            },
+            Err(err) => {
+                eprintln!("Body Error: {}", err);
+                return;
+            }
+        }
+    }
+
+    println!("\n\nDone!");
 }