Very simple version of Isolates.

tests/isolate/browser/compute_this_script_browser_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.
-
-// Test that spawn works even when there are many script files in the page.
-// This requires computing correctly the URL to the orignal script, so we can
-// pass it to the web worker APIs.
-library compute_this_script;
-
-import 'dart:html';
-import 'dart:isolate';
-import 'package:unittest/unittest.dart';
-import 'package:unittest/html_config.dart';
-
-child() {
-  var sink;
-  stream.listen((msg) {
-    sink = msg;
-  }, onDone: () {
-    sink.add("done");
-    sink.close();
-  });
-}
-
-main() {
-  useHtmlConfiguration();
-  var script = new ScriptElement();
-  document.body.append(script);
-  test('spawn with other script tags in page', () {
-    var box = new MessageBox();
-    box.stream.listen(expectAsync1((msg) {
-      expect(msg, equals("done"));
-    }));
-
-    IsolateSink s = streamSpawnFunction(child);
-    s.add(box.sink);
-    s.close();
-  });
-}