code: func SizeToString(s int64) string {
  	v := float64(s)
  	i := 0
  	for ; i < len(units); i++ {
  		if v < 1024. {
  			break
  		}
  		v /= 1024.
  	}
  	if i == 0 {
  		return fmt.Sprintf("%d%s", s, units[i])
  	}
  	if v >= 10 {
  		return fmt.Sprintf("%.1f%s", v, units[i])
  	}
  	return fmt.Sprintf("%.2f%s", v, units[i])
  }
docs: // SizeToString pretty prints file size (given as number of bytes).