Very simple version of Isolates.

runtime/bin/io_service_patch.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.
 
 patch class _IOService {
   // Lazy initialize service ports, 32 per isolate.
   static const int _SERVICE_PORT_COUNT = 32;
   static List<SendPort> _servicePort = new List(_SERVICE_PORT_COUNT);
   static ReceivePort _receivePort;
   static SendPort _replyToPort;
@@ skipping 12 matching lines @@
     _servicePort[index].send([id, request, data], _replyToPort);
     return completer.future;
   }
 
   static void _initialize(int index) {
     if (_servicePort[index] == null) {
       _servicePort[index] = _newServicePort();
     }
     if (_receivePort == null) {
       _receivePort = new ReceivePort();
-      _replyToPort = _receivePort.toSendPort();
-      _receivePort.receive((data, _) {
+      _replyToPort = _receivePort.sendPort;
+      StreamSubscription subscription;
+      subscription = _receivePort.listen((data) {

[Ivan Posva, 2013/10/24 06:48:38]

This is one of those occasions where I would expect you to use the
RawReceivePort as you do not want to have to deal with streams, zones or
anything else when delivering the raw IO events from epoll to the IO subsystem.

[floitsch, 2013/10/24 16:15:58]

just wasn't changed back yet.
done.

         assert(data is List && data.length == 2);
         _messageMap.remove(data[0]).complete(data[1]);
         if (_messageMap.length == 0) {
           _id = 0;
-          _receivePort.close();
+          subscription.cancel();
           _receivePort = null;
         }
       });
     }
   }
 
   static int _getNextId() {
     if (_id == 0x7FFFFFFF) _id = 0;
     return _id++;
   }
 
   static SendPort _newServicePort() native "IOService_NewServicePort";
 }