Add a simple "hello" example

examples/hello.rs

@@ -0,0 +1,25 @@
+extern crate futures;
+extern crate tokio_core;
+
+use futures::stream::Stream;
+use tokio_core::reactor::Core;
+use tokio_core::net::TcpListener;
+
+fn main() {
+    let mut core = Core::new().unwrap();
+    let address = "127.0.0.1:8080".parse().unwrap();
+    let listener = TcpListener::bind(&address, &core.handle()).unwrap();
+
+    let addr = listener.local_addr().unwrap();
+    println!("Listening for connections on {}", addr);
+
+    let clients = listener.incoming();
+    let welcomes = clients.and_then(|(socket, _peer_addr)| {
+        tokio_core::io::write_all(socket, b"Hello!\n")
+    });
+    let server = welcomes.for_each(|(_socket, _welcome)| {
+        Ok(())
+    });
+
+    core.run(server).unwrap();
+}