code: func (u *volumeUtil) ReadDir(fullPath string) ([]string, error) {
  	dir, err := os.Open(fullPath)
  	if err != nil {
  		return nil, err
  	}
  	defer dir.Close()
  
  	files, err := dir.Readdirnames(-1)
  	if err != nil {
  		return nil, err
  	}
  	return files, nil
  }
docs: // ReadDir returns a list all the files under the given directory