Very simple version of Isolates.

tests/isolate/port_test.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.
 
 // Test properties of ports.
 // Note: unittest.dart depends on ports, in particular on the behaviour tested
 // here. To keep things simple, we don't use the unittest library here.
 
 library PortTest;
 import "package:expect/expect.dart";
 import 'dart:isolate';
 import '../../pkg/unittest/lib/matcher.dart';
 
 main() {
   testHashCode();
   testEquals();
   testMap();
 }
 
 void testHashCode() {
   ReceivePort rp0 = new ReceivePort();
   ReceivePort rp1 = new ReceivePort();
-  Expect.equals(rp0.toSendPort().hashCode, rp0.toSendPort().hashCode);
-  Expect.equals(rp1.toSendPort().hashCode, rp1.toSendPort().hashCode);
+  Expect.equals(rp0.sendPort.hashCode, rp0.sendPort.hashCode);
+  Expect.equals(rp1.sendPort.hashCode, rp1.sendPort.hashCode);
   rp0.close();
   rp1.close();
 }
 
 void testEquals() {
   ReceivePort rp0 = new ReceivePort();
   ReceivePort rp1 = new ReceivePort();
-  Expect.equals(rp0.toSendPort(), rp0.toSendPort());
-  Expect.equals(rp1.toSendPort(), rp1.toSendPort());
-  Expect.isFalse(rp0.toSendPort() == rp1.toSendPort());
+  Expect.equals(rp0.sendPort, rp0.sendPort);
+  Expect.equals(rp1.sendPort, rp1.sendPort);
+  Expect.isFalse(rp0.sendPort == rp1.sendPort);
   rp0.close();
   rp1.close();
 }
 
 void testMap() {
   ReceivePort rp0 = new ReceivePort();
   ReceivePort rp1 = new ReceivePort();
   final map = new Map<SendPort, int>();
-  map[rp0.toSendPort()] = 42;
-  map[rp1.toSendPort()] = 87;
-  Expect.equals(map[rp0.toSendPort()], 42);
-  Expect.equals(map[rp1.toSendPort()], 87);
+  map[rp0.sendPort] = 42;
+  map[rp1.sendPort] = 87;
+  Expect.equals(map[rp0.sendPort], 42);
+  Expect.equals(map[rp1.sendPort], 87);
 
-  map[rp0.toSendPort()] = 99;
-  Expect.equals(map[rp0.toSendPort()], 99);
-  Expect.equals(map[rp1.toSendPort()], 87);
+  map[rp0.sendPort] = 99;
+  Expect.equals(map[rp0.sendPort], 99);
+  Expect.equals(map[rp1.sendPort], 87);
 
-  map.remove(rp0.toSendPort());
-  Expect.isFalse(map.containsKey(rp0.toSendPort()));
-  Expect.equals(map[rp1.toSendPort()], 87);
+  map.remove(rp0.sendPort);
+  Expect.isFalse(map.containsKey(rp0.sendPort));
+  Expect.equals(map[rp1.sendPort], 87);
 
-  map.remove(rp1.toSendPort());
-  Expect.isFalse(map.containsKey(rp0.toSendPort()));
-  Expect.isFalse(map.containsKey(rp1.toSendPort()));
+  map.remove(rp1.sendPort);
+  Expect.isFalse(map.containsKey(rp0.sendPort));
+  Expect.isFalse(map.containsKey(rp1.sendPort));
 
   rp0.close();
   rp1.close();
 }