// as mandated by RFC 3986 Section 6.2.3.
func removeEmptyPort(host string) string {
	if hasPort(host) {
		return strings.TrimSuffix(host, ":")
	}
	return host
}

func isNotToken(r rune) bool {
	return !httpguts.IsTokenRune(r)
}

// stringContainsCTLByte reports whether s contains any ASCII control character.
func stringContainsCTLByte(s string) bool {
	for i := 0; i < len(s); i++ {