return backingValueGraph.putEdgeValue(nodeU, nodeV, Presence.EDGE_EXISTS) == null;
  }

  @Override
  public boolean putEdge(EndpointPair<N> endpoints) {
    validateEndpoints(endpoints);
    return putEdge(endpoints.nodeU(), endpoints.nodeV());
  }

  @Override
  public boolean removeNode(N node) {
    return backingValueGraph.removeNode(node);
  }

  @Override

  public boolean hasEdgeConnecting(EndpointPair<N> endpoints) {
    checkNotNull(endpoints);
    if (!isOrderingCompatible(endpoints)) {
      return false;
    }
    N nodeU = endpoints.nodeU();
    N nodeV = endpoints.nodeV();
    return nodes().contains(nodeU) && successors(nodeU).contains(nodeV);
  }

  /**
   * Throws {@code IllegalArgumentException} if the ordering of {@code endpoints} is not compatible

var errEtcdUnreachable = errors.New("etcd is unreachable, please check your endpoints")

func etcdErrToErr(err error, etcdEndpoints []string) error {
	if err == nil {
		return nil
	}
	switch err {
	case context.DeadlineExceeded:
		return fmt.Errorf("%w %s", errEtcdUnreachable, etcdEndpoints)
	default:
		return fmt.Errorf("unexpected error %w from etcd, please check your endpoints %s", err, etcdEndpoints)
	}
}

			return err
		}
	}
	if r.Target.Endpoint == "" && !r.Target.Creds.Empty() {
		return errInvalidArgument
	}

	if r.Source.Endpoint == "" && !r.Source.Creds.Empty() {
		return errInvalidArgument
	}

	if r.Source.Endpoint != "" && !r.Source.Type.isMinio() && !r.Source.ValidPath() {
		return errInvalidArgument
	}

	if r.Target.Endpoint != "" && !r.Target.Type.isMinio() && !r.Target.ValidPath() {

    return backingValueGraph.putEdgeValue(nodeU, nodeV, Presence.EDGE_EXISTS) == null;
  }

  @Override
  public boolean putEdge(EndpointPair<N> endpoints) {
    validateEndpoints(endpoints);
    return putEdge(endpoints.nodeU(), endpoints.nodeV());
  }

  @Override
  public boolean removeNode(N node) {
    return backingValueGraph.removeNode(node);
  }

  @Override

notify_webhook        publish bucket notifications to webhook endpoints
notify_amqp           publish bucket notifications to AMQP endpoints
notify_kafka          publish bucket notifications to Kafka endpoints
notify_mqtt           publish bucket notifications to MQTT endpoints
notify_nats           publish bucket notifications to NATS endpoints
notify_nsq            publish bucket notifications to NSQ endpoints

  public boolean hasEdgeConnecting(EndpointPair<N> endpoints) {
    return delegate().hasEdgeConnecting(endpoints);
  }

  @Override
  public @Nullable V edgeValueOrDefault(N nodeU, N nodeV, @Nullable V defaultValue) {
    return delegate().edgeValueOrDefault(nodeU, nodeV, defaultValue);
  }

  @Override
  public @Nullable V edgeValueOrDefault(EndpointPair<N> endpoints, @Nullable V defaultValue) {

  @Override
  public boolean hasEdgeConnecting(EndpointPair<N> endpoints) {
    return delegate().hasEdgeConnecting(endpoints);
  }

  @Override
  public Optional<V> edgeValue(N nodeU, N nodeV) {
    return delegate().edgeValue(nodeU, nodeV);
  }

  @Override
  public Optional<V> edgeValue(EndpointPair<N> endpoints) {
    return delegate().edgeValue(endpoints);
  }

  @Override

  public Set<E> edgesConnecting(EndpointPair<N> endpoints) {
    return delegate().edgesConnecting(endpoints);
  }

  @Override
  public @Nullable E edgeConnectingOrNull(N nodeU, N nodeV) {
    return delegate().edgeConnectingOrNull(nodeU, nodeV);
  }

  @Override
  public @Nullable E edgeConnectingOrNull(EndpointPair<N> endpoints) {
    return delegate().edgeConnectingOrNull(endpoints);
  }

  @Override

- Endpoints resources created by the Endpoints controller now have a label indicating this.
  (Users creating Endpoints by hand _can_ also add this label themselves, but they ought