clientv3/balancer/resolver/endpoint/endpoint.go
func ParseEndpoint(endpoint string) (proto string, host string, scheme string) {
	proto = "tcp"
	host = endpoint
	url, uerr := url.Parse(endpoint)
	if uerr != nil || !strings.Contains(endpoint, "://") {
		return proto, host, scheme
	}
	scheme = url.Scheme

	// strip scheme:// prefix since grpc dials by host
	host = url.Host
	switch url.Scheme {
	case "http", "https":
	case "unix", "unixs":
		proto = "unix"
		host = url.Host + url.Path
	default:
		proto, host = "", ""
	}
	return proto, host, scheme
}
func ParseEndpoint(endpoint string) (proto string, host string, scheme string) {
	proto = "tcp"
	host = endpoint
	url, uerr := url.Parse(endpoint)
	if uerr != nil || !strings.Contains(endpoint, "://") {
		return proto, host, scheme
	}
	scheme = url.Scheme

	// strip scheme:// prefix since grpc dials by host
	host = url.Host
	switch url.Scheme {
	case "http", "https":
	case "unix", "unixs":
		proto = "unix"
		host = url.Host + url.Path
	default:
		proto, host = "", ""
	}
	return proto, host, scheme
}
// ParseEndpoint endpoint parses an endpoint of the form
// (http|https)://<host>*|(unix|unixs)://<path>)
// and returns a protocol ('tcp' or 'unix'),
// host (or filepath if a unix socket),
// scheme (http, https, unix, unixs).