code: func FriendlyBytes(bytes int64) string {
  	fbytes := float64(bytes)
  	base := 1024
  	pre := []string{"K", "M", "G", "T", "P", "E"}
  	if fbytes < float64(base) {
  		return fmt.Sprintf("%v B", fbytes)
  	}
  	exp := int(math.Log(fbytes) / math.Log(float64(base)))
  	index := exp - 1
  	return fmt.Sprintf("%.2f %sB", fbytes/math.Pow(float64(base), float64(exp)), pre[index])
  }
docs: // FriendlyBytes returns a string with the given bytes int64
  // represented as a size, such as 1KB, 10MB, etc...