SendPort + ReceivePort changes:

samples/tests/samples/src/proxy/PromiseBasedTest.dart

Index: samples/tests/samples/src/proxy/PromiseBasedTest.dart
diff --git a/samples/tests/samples/src/proxy/PromiseBasedTest.dart b/samples/tests/samples/src/proxy/PromiseBasedTest.dart
index 441a237b507b796585a5bc6cf706d9229be2c6c9..b9b17762537e8b4989a128090930771e91549f4b 100644
--- a/samples/tests/samples/src/proxy/PromiseBasedTest.dart
+++ b/samples/tests/samples/src/proxy/PromiseBasedTest.dart
@@ -59,8 +59,9 @@ void expandedTest(TestExpectation expect) {
   proxy.send([42]);  // Seed the isolate.
   Promise<SendPort> sendCompleter = proxy.call([87]);
   Promise<int> result = new Promise<int>();
-  ReceivePort receivePort = new ReceivePort.singleShot();
+  ReceivePort receivePort = new ReceivePort();
   receivePort.receive((var msg, SendPort _) {
+    receivePort.close();
     //print("test completer");
     result.complete(msg[0]);
   });