docs(examples): Update the example hello (#1852)

liufuyang · seanmonstar · commit 67c4781734cf · 2019-07-10T09:43:56.000-07:00
diff --git a/examples/hello.rs b/examples/hello.rs
@@ -5,19 +5,21 @@ extern crate pretty_env_logger;
 
 use hyper::{Body, Request, Response, Server};
 use hyper::service::{make_service_fn, service_fn};
-use hyper::rt;
 
 async fn hello(_: Request<Body>) -> Result<Response<Body>, hyper::Error> {
     Ok(Response::new(Body::from("Hello World!")))
 }
 
-async fn serve() {
+#[tokio::main]
+pub async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    pretty_env_logger::init();
+
     let addr = ([127, 0, 0, 1], 3000).into();
 
     let server = Server::bind(&addr)
         .serve(make_service_fn(|_| {
             // This is the `Service` that will handle the connection.
-            // `service_fn_ok` is a helper to convert a function that
+            // `service_fn` is a helper to convert a function that
             // returns a Response into a `Service`.
             async {
                 Ok::<_, hyper::Error>(service_fn(hello))
@@ -26,13 +28,7 @@ async fn serve() {
 
     println!("Listening on http://{}", addr);
 
-    if let Err(e) = server.await {
-        eprintln!("server error: {}", e);
-    }
-}
-
-fn main() {
-    pretty_env_logger::init();
+    server.await?;
 
-    rt::run(serve());
+    Ok(())
 }
