Very simple version of Isolates.

tests/standalone/io/echo_server_stream_test.dart

 // Copyright (c) 2013, 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.
 //
 // Echo server test program to test socket streams.
 //
 // VMOptions=
 // VMOptions=--short_socket_read
 // VMOptions=--short_socket_write
 // VMOptions=--short_socket_read --short_socket_write
 
 library ServerTest;
 
 import "package:expect/expect.dart";
+import "package:async_helper/async_helper.dart";
 import "dart:async";
 import "dart:io";
 import "dart:isolate";
 part "testing_server.dart";
 
 class EchoServerGame {
 
   static const MSGSIZE = 10;
   static const MESSAGES = 100;
   static const FIRSTCHAR = 65;
 
   EchoServerGame.start()
-      : _receivePort = new ReceivePort(),
-        _sendPort = null,
-        _buffer = new List<int>(MSGSIZE),
+      : _buffer = new List<int>(MSGSIZE),
         _messages = 0 {
     for (int i = 0; i < MSGSIZE; i++) {
       _buffer[i] = FIRSTCHAR + i;
     }
-    _sendPort = spawnFunction(startEchoServer);
     initialize();
   }
 
   void sendData() {
     int offset = 0;
     List<int> data;
 
     void onData(List<int> data) {
       int bytesRead = data.length;
       for (int i = 0; i < data.length; i++) {
@@ skipping 28 matching lines @@
       data = new List<int>(MSGSIZE);
     }
 
     Socket.connect(TestingServer.HOST, _port).then((s) {
       _socket = s;
       connectHandler();
     });
   }
 
   void initialize() {
-    _receivePort.receive((var message, SendPort replyTo) {
-      _port = message;
+    var receivePort = new ReceivePort();
+    var remote = Isolate.spawn(startEchoServer, receivePort.sendPort);
+    receivePort.first.then((msg) {
+      this._port = msg[0];
+      this._closeSendPort = msg[1];
       sendData();
     });
-    _sendPort.send(TestingServer.INIT, _receivePort.toSendPort());
   }
 
   void shutdown() {
-    _sendPort.send(TestingServer.SHUTDOWN, _receivePort.toSendPort());
-    _receivePort.close();
+    _closeSendPort.send(null);
+    asyncEnd();
   }
 
   int _port;
-  ReceivePort _receivePort;
-  SendPort _sendPort;
+  SendPort _closeSendPort;
   Socket _socket;
   List<int> _buffer;
   int _messages;
 }
 
 
-void startEchoServer() {
+void startEchoServer(SendPort replyPort) {
   var server = new EchoServer();
-  port.receive(server.dispatch);
+  server.init().then((port) {
+    replyPort.send([port, server.closeSendPort]);
+  });
 }
 
 
 class EchoServer extends TestingServer {
 
   static const int MSGSIZE = EchoServerGame.MSGSIZE;
 
   void onConnection(Socket connection) {
     List<int> buffer = new List<int>(MSGSIZE);
     int offset = 0;
@@ skipping 19 matching lines @@
       var trace = getAttachedStackTrace(e);
       if (trace != null) msg += "\nStackTrace: $trace";
       Expect.fail(msg);
     }
 
     connection.listen(dataReceived, onError: errorHandler);
   }
 }
 
 main() {
+  asyncStart();
   EchoServerGame echoServerGame = new EchoServerGame.start();
 }