code: func isControlCharacter(b []byte) bool {
  	for len(b) > 0 {
  		r, size := utf8.DecodeRune(b)
  		if unicode.IsControl(r) || unicode.Is(unicode.C, r) {
  			return true
  		}
  		b = b[size:]
  	}
  	return false
  }
docs: // isControlCharacter checks if Control characters are included in the given bytes