code: func FileLastModified(path string) (time.Time, error) {
  	f, err := os.Open(path)
  	if err != nil {
  		return zeroTime, err
  	}
  	fileInfo, err := f.Stat()
  	f.Close()
  	if err != nil {
  		return zeroTime, err
  	}
  	return fsModTime(fileInfo.ModTime()), nil
  }
docs: // FileLastModified returns last modified time for the file.