Very simple version of Isolates.

tests/isolate/count_stream_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.
-
-library CountTest;
-import '../../pkg/unittest/lib/unittest.dart';
-import 'dart:isolate';
-
-void countMessages() {
-  int count = 0;
-  IsolateSink replySink;
-  bool isFirst = true;
-  stream.listen((msg) {
-    if (isFirst) {
-      replySink = msg;
-      isFirst = false;
-      return;
-    }
-    replySink.add(count);
-    count++;
-  }, onDone: () {
-    expect(count, 10);
-    replySink.close();
-  });
-}
-
-void main() {
-  test("count 10 consecutive stream messages", () {
-    int count = 0;
-    MessageBox box = new MessageBox();
-    IsolateSink remote = streamSpawnFunction(countMessages);
-    remote.add(box.sink);
-    box.stream.listen(expectAsync1((remoteCount) {
-      expect(remoteCount, count);
-      count++;
-      if (count < 10) {
-        remote.add(null);
-      } else {
-        remote.close();
-      }
-    }, count: 10), onDone: expectAsync0(() {
-      expect(count, 10);
-    }));
-    remote.add(null);
-  });
-}