anchor.diff:          postCallbackCompleter.complete();
         }
       });
  -    
  +
       // Publish a tracking record for this request (synchronously).
       _controller.add(new TrackedRequest._private(
           request, preCallbackCompleter.future, postCallbackCompleter.future));
  -    
  +
       // To be called when an event has been processed. Only on the first one, this
       // should complete the future sent on the tracking stream, indicating a response
       // has been processed.
  
positive.code:       closed = true;
        c.close();
      });
      
      return c.stream;
    }
  }
  
negative.code:         postCallbackCompleter.complete(error);
        }
      }
  
      // Subscribe to the stream. On a new value or error, publish it to the controller.
      sub = responseStream.listen((entity) {
        sawValue = true;
  