code: func newNilFutureResult() chan *response {
  	responseChan := make(chan *response, 1)
  	responseChan <- &response{result: nil, err: nil}
  	return responseChan
  }
docs: // newNilFutureResult returns a new future result channel that already has the
  // result waiting on the channel with the reply set to nil.  This is useful
  // to ignore things such as notifications when the caller didn't specify any
  // notification handlers.