anchor.diff:  
     int get requestId => request.requestId;
   
  -
     @override
     void add(event) {
       _output.add(event);
  
positive.code: typedef void DoneFunction(Response);
  
  class Response implements StreamSink {
  
    //TODO: move isolate to response object
    //TODO: move control / data / error ports into response object from connection_handler
  
  
negative.code:   @override
    Future addStream(Stream stream) => _output.addStream(stream);
  
    Future close() => _output.close();
  
    void header(dynamic entry) {
      _header.add(entry.toString());
    }
  
    void _createListener(DataFunction onData, DataFunction onError, DoneFunction onDone) {
      _output.stream.listen((data) {
  