Very simple version of Isolates.

tests/lib/async/schedule_microtask4_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.
-
-library run_async_test;
-
-import 'package:async_helper/async_helper.dart';
-import 'dart:async';
-import 'dart:isolate';
-
-void startTest(SendPort finishPort, replyPort) {
-  int invokedCallbacks = 0;
-
-  for (int i = 0; i < 100; i++) {
-    scheduleMicrotask(() {
-      invokedCallbacks++;
-      if (invokedCallbacks == 100) finishPort.send("done");
-      if (i == 50) throw new UnsupportedError("ignore exception");
-    });
-  }
-}
-
-runTest() {
-  port.receive(startTest);
-}
-
-bool globalErrorHandler(IsolateUnhandledException e) {
-  return e.source is UnsupportedError && e.source.message == "ignore exception";
-}
-
-main() {
-  asyncStart();
-  var port = new ReceivePort();
-  var timer;
-  SendPort otherIsolate = spawnFunction(runTest, globalErrorHandler);
-  otherIsolate.send(port.toSendPort());
-  port.receive((msg, replyPort) {
-    port.close();
-    timer.cancel();
-    asyncEnd();
-  });
-  timer = new Timer(const Duration(seconds: 2), () { throw "failed"; });
-}