code: func (l *lcowfs) readDirNames(dirname string) ([]string, error) {
  	f, err := l.Open(dirname)
  	if err != nil {
  		return nil, err
  	}
  	files, err := f.Readdir(-1)
  	f.Close()
  	if err != nil {
  		return nil, err
  	}
  
  	names := make([]string, len(files), len(files))
  	for i := range files {
  		names[i] = files[i].Name()
  	}
  
  	sort.Strings(names)
  	return names, nil
  }
docs: // readDirNames reads the directory named by dirname and returns
  // a sorted list of directory entries.