code: func (d *kubeDockerClient) redirectResponseToOutputStream(tty bool, outputStream, errorStream io.Writer, resp io.Reader) error {
  	if outputStream == nil {
  		outputStream = ioutil.Discard
  	}
  	if errorStream == nil {
  		errorStream = ioutil.Discard
  	}
  	var err error
  	if tty {
  		_, err = io.Copy(outputStream, resp)
  	} else {
  		_, err = dockerstdcopy.StdCopy(outputStream, errorStream, resp)
  	}
  	return err
  }
docs: // redirectResponseToOutputStream redirect the response stream to stdout and stderr. When tty is true, all stream will
  // only be redirected to stdout.