func (e *Endpoints) ClusterAddress() string {
	e.mu.RLock()
	defer e.mu.RUnlock()

	listener := e.listeners[cluster]
	if listener == nil {
		return ""
	}
	return listener.Addr().String()
}
func (e *Endpoints) ClusterAddress() string {
	e.mu.RLock()
	defer e.mu.RUnlock()

	listener := e.listeners[cluster]
	if listener == nil {
		return ""
	}
	return listener.Addr().String()
}
// ClusterAddress returns the cluster addresss of the cluster endpoint, or an
// empty string if there's no cluster endpoint.