code: func saveVolumeData(dir string, fileName string, data map[string]string) error {
  	dataFilePath := filepath.Join(dir, fileName)
  	klog.V(4).Info(log("saving volume data file [%s]", dataFilePath))
  	file, err := os.Create(dataFilePath)
  	if err != nil {
  		klog.Error(log("failed to save volume data file %s: %v", dataFilePath, err))
  		return err
  	}
  	defer file.Close()
  	if err := json.NewEncoder(file).Encode(data); err != nil {
  		klog.Error(log("failed to save volume data file %s: %v", dataFilePath, err))
  		return err
  	}
  	klog.V(4).Info(log("volume data file saved successfully [%s]", dataFilePath))
  	return nil
  }
docs: // saveVolumeData persists parameter data as json file at the provided location