Very simple version of Isolates.

tests/isolate/spawn_uri_nested_child1_vm_isolate.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.
 
 // Example of nested spawning of isolates from a URI
 // Note: the following comment is used by test.dart to additionally compile the
 // other isolate's code.
 library NestedSpawnUriChild1Library;
 import 'dart:isolate';
 
-main() {
+main(List<String> args, message) {
   ReceivePort port2 = new ReceivePort();
-  port2.receive((msg, SendPort replyTo) {
+  port2.listen((msg) {
+    if (msg != "re: hi") throw "Bad response: $msg";
     port2.close();
   });
 
-  SendPort s = spawnUri('spawn_uri_nested_child2_vm_isolate.dart');
-  s.send('hi', port2.toSendPort());
+  Isolate.spawnUri(Uri.parse('spawn_uri_nested_child2_vm_isolate.dart'),
+                   ['hi'], port2.sendPort);
 
-  port.receive((message, SendPort replyTo) {
-    var result = message;
-    replyTo.send(result);
-  });
+  var data = message[0];
+  var replyTo = message[1];
+  replyTo.send(data);
 }