}

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

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

  @Override
  public boolean hasEdgeConnecting(N nodeU, N nodeV) {