Update example to not broadcast close messages.

In the event that the client sends a close message,
it is broadcast to other clients closing them as well.

examples/server.rs

@@ -52,7 +52,13 @@ async fn handle_connection(peer_map: PeerMap, raw_stream: TcpStream, addr: Socke
 
     let (outgoing, incoming) = ws_stream.split();
 
-    let broadcast_incoming = incoming.try_for_each(|msg| {
+    let broadcast_incoming = incoming
+        .try_filter(|msg| {
+            // Broadcasting a Close message from one client
+            // will close the other clients.
+            future::ready(!msg.is_close())
+        })
+        .try_for_each(|msg| {
             println!(
                 "Received a message from {}: {}",
                 addr,