Very simple version of Isolates.

samples/chat/chat_server.dart

Index: samples/chat/chat_server.dart
diff --git a/samples/chat/chat_server.dart b/samples/chat/chat_server.dart
index 537068b14bef9b983f0be6e8104e3e041f2d093f..c581538a99b56af8ee00a9e073a71050f7e6425e 100644
--- a/samples/chat/chat_server.dart
+++ b/samples/chat/chat_server.dart
@@ -16,12 +16,13 @@ void main() {
   // stopAfter for that.
   int stopAfter;
 
-  var serverPort = spawnFunction(startChatServer);
-  ServerMain serverMain =
-      new ServerMain.start(serverPort, DEFAULT_HOST, DEFAULT_PORT);
+  spawnChatServer().then((serverPort) {
+    ServerMain serverMain =
+        new ServerMain.start(serverPort, DEFAULT_HOST, DEFAULT_PORT);
 
-  // Start a shutdown timer if requested.
-  if (stopAfter != null) {
-    new Timer(new Duration(seconds: stopAfter), serverMain.shutdown);
-  }
+    // Start a shutdown timer if requested.
+    if (stopAfter != null) {
+      new Timer(new Duration(seconds: stopAfter), serverMain.shutdown);
+    }
+  });
 }