Very simple version of Isolates.

pkg/serialization/test/serialization_test.dart

Index: pkg/serialization/test/serialization_test.dart
diff --git a/pkg/serialization/test/serialization_test.dart b/pkg/serialization/test/serialization_test.dart
index 83232c91ace606b1a8c3158892a1e0bbec8ecc0a..832330a27d08d0cbb7ede38bfcdb5f05533d090e 100644
--- a/pkg/serialization/test/serialization_test.dart
+++ b/pkg/serialization/test/serialization_test.dart
@@ -549,8 +549,9 @@ void main() {
       n3.parent = n1;
       var s = nodeSerializerReflective(n1);
       var output = s.write(n2);
-      var port = spawnFunction(echo);
-      return port.call(output).then(verify);
+      ReceivePort port = new ReceivePort();
+      var remote = Isolate.spawn(echo, [port.sendPort, output]);
+      port.first.then(verify);
   });
 }
 
@@ -808,8 +809,8 @@ class PersonRuleReturningMapWithNonStringKey extends CustomRule {
  * Function used in an isolate to make sure that the output passes through
  * isolate serialization properly.
  */
-void echo() {
-  port.receive((msg, reply) {
-    reply.send(msg);
-  });
+void echo(initialMessage) {
+  var reply = initialMessage[0];
+  var msg = initialMessage[1];
+  reply.send(msg);
 }