cookie.go
func appendResponseCookieBytes(dst []byte, cookies []argsKV) []byte {
	for i, n := 0, len(cookies); i < n; i++ {
		kv := &cookies[i]
		dst = append(dst, kv.value...)
		if i+1 < n {
			dst = append(dst, ';', ' ')
		}
	}
	return dst
}
func appendResponseCookieBytes(dst []byte, cookies []argsKV) []byte {
	for i, n := 0, len(cookies); i < n; i++ {
		kv := &cookies[i]
		dst = append(dst, kv.value...)
		if i+1 < n {
			dst = append(dst, ';', ' ')
		}
	}
	return dst
}
// For Response we can not use the above function as response cookies
// already contain the key= in the value.