code: func (c Config) WriteTo(w io.Writer) (int64, error) {
  	data, err := json.Marshal(c)
  	if err != nil {
  		return int64(len(data)), err
  	}
  	return io.Copy(w, bytes.NewReader(data))
  }
docs: // WriteTo implements the io.WriteTo interface. This should
  // be used to save or print out the configuration information.