code: func (r *reader) ReadStatusLine() (Version, int, string, error) {
  	version, err := r.ReadVersion()
  	if err != nil {
  		return Version{}, 0, "", err
  	}
  	code, err := r.ReadStatusCode()
  	if err != nil {
  		return Version{}, 0, "", err
  	}
  	msg, _, err := r.ReadLine()
  	return version, code, string(msg), err
  }
docs: // ReadStatusLine reads the status line.