anchor.diff:          }));
         }));
         handler.handle(TEST_GET_REQUEST).listen(expectAsync1((entity) {
  -        print("Inside callback: $entity");
           x = entity['x'];
         }, count: 2));
       });
  
positive.code:         .build();
        var tracker = new RequestTrackingTransformer();
        var handler = bareHandler.transformResponses(tracker);
        
        var x = ' ';
        tracker.trackingStream.listen(expectAsync1((event) {
          expect(event.request, equals(TEST_GET_REQUEST));
  
negative.code:         .build();
        var tracker = new RequestTrackingTransformer();
        var handler = bareHandler.transformResponses(tracker);
  
        tracker.trackingStream.listen(expectAsync1((event) {
          expect(event.request, equals(TEST_GET_REQUEST));
          event.onFirstResponse.catchError(expectAsync1((error) {
  