Very simple version of Isolates.

samples/chat/chat_server.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library chat_server;
 import 'dart:io';
 import 'dart:isolate';
 import 'chat_server_lib.dart';
 
 
 const DEFAULT_PORT = 8123;
 const DEFAULT_HOST = "127.0.0.1";
 
 void main() {
   // For profiling stopping after some time is convenient. Set
   // 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);
+    }
+  });
 }