code: func (r *responseRecorderWithoutCloseNotify) Flush() {
  	if !r.streamingResponseStarted {
  		utils.CopyHeaders(r.responseWriter.Header(), r.Header())
  		r.responseWriter.WriteHeader(r.Code)
  		r.streamingResponseStarted = true
  	}
  
  	_, err := r.responseWriter.Write(r.Body.Bytes())
  	if err != nil {
  		r.logger.Errorf("Error writing response in responseRecorder: %v", err)
  		r.err = err
  	}
  	r.Body.Reset()
  
  	if flusher, ok := r.responseWriter.(http.Flusher); ok {
  		flusher.Flush()
  	}
  }
docs: // Flush sends any buffered data to the client.