code: func (l *localFileInfo) ReadDir() ([]FileInfo, error) {
  	f, err := os.Open(l.filePath)
  	if err != nil {
  		return nil, trace.Wrap(err)
  	}
  
  	fis, err := f.Readdir(0)
  	if err != nil {
  		return nil, trace.Wrap(err)
  	}
  
  	infos := make([]FileInfo, len(fis))
  	for i := range fis {
  		fi := fis[i]
  		info, err := makeFileInfo(filepath.Join(l.GetPath(), fi.Name()))
  		if err != nil {
  			return nil, trace.Wrap(err)
  		}
  		infos[i] = info
  	}
  
  	return infos, nil
  }
docs: // ReadDir returns all files in this directory