clientv3/balancer/resolver/endpoint/endpoint.go
func ParseHostPort(hostPort string) (host string, port string) {
	parts := strings.SplitN(hostPort, ":", 2)
	host = parts[0]
	if len(parts) > 1 {
		port = parts[1]
	}
	return host, port
}
func ParseHostPort(hostPort string) (host string, port string) {
	parts := strings.SplitN(hostPort, ":", 2)
	host = parts[0]
	if len(parts) > 1 {
		port = parts[1]
	}
	return host, port
}
// ParseHostPort splits a "<host>:<port>" string into the host and port parts.
// The port part is optional.