util.go
func genQueryOptions(q url.Values) string {
	if s := q.Encode(); s != "" {
		return "?" + s
	}
	return ""
}
func genQueryOptions(q url.Values) string {
	if s := q.Encode(); s != "" {
		return "?" + s
	}
	return ""
}
// genQueryOptions generates standard query options.