/**
   * Returns a live view of the edges whose {@link #incidentNodes(Object) incident nodes} in this
   * network include {@code node}.
   *
   * <p>This is equal to the union of {@link #inEdges(Object)} and {@link #outEdges(Object)}.
   *
   * <p>If {@code node} is removed from the network after this method is called, the {@code Set}
   * {@code view} returned by this method will be invalidated, and will throw {@code

      return network.incidentEdges(node);
    }

    @Override
    public Set<E> inEdges(N node) {
      return network.inEdges(node);
    }

    @Override
    public Set<E> outEdges(N node) {
      return network.outEdges(node);
    }

    @Override
    public EndpointPair<N> incidentNodes(E edge) {
      return network.incidentNodes(edge);
    }

    @Override

      }
    };
  }

  @Override
  public Set<E> inEdges() {
    return Collections.unmodifiableSet(inEdgeMap.keySet());
  }

  @Override
  public Set<E> outEdges() {
    return Collections.unmodifiableSet(outEdgeMap.keySet());
  }

  @Override
  public N adjacentNode(E edge) {
    // Since the reference node is defined to be 'source' for directed graphs,

 */
interface NetworkConnections<N, E> {

  Set<N> adjacentNodes();

  Set<N> predecessors();

  Set<N> successors();

  Set<E> incidentEdges();

  Set<E> inEdges();

  Set<E> outEdges();

  /**
   * Returns the set of edges connecting the origin node to {@code node}. For networks without
   * parallel edges, this set cannot be of size greater than one.
   */
  Set<E> edgesConnecting(N node);

  public Set<E> incidentEdges() {
    return Collections.unmodifiableSet(incidentEdgeMap.keySet());
  }

  @Override
  public Set<E> inEdges() {
    return incidentEdges();
  }

  @Override
  public Set<E> outEdges() {
    return incidentEdges();
  }

  @Override
  public N adjacentNode(E edge) {
    // We're relying on callers to call this method only with an edge that's in the graph.

    public int outDegree(N node) {
      return delegate().inDegree(node); // transpose
    }

    @Override
    public Set<E> inEdges(N node) {
      return delegate().outEdges(node); // transpose
    }

    @Override
    public Set<E> outEdges(N node) {
      return delegate().inEdges(node); // transpose
    }

    @Override
    public EndpointPair<N> incidentNodes(E edge) {

    public int outDegree(N node) {
      return delegate().inDegree(node); // transpose
    }

    @Override
    public Set<E> inEdges(N node) {
      return delegate().outEdges(node); // transpose
    }

    @Override
    public Set<E> outEdges(N node) {
      return delegate().inEdges(node); // transpose
    }

    @Override
    public EndpointPair<N> incidentNodes(E edge) {

        }

        orderedNodeConnectionsBuilder.add(new NodeConnection.Pred<>(predecessor));
        predecessorCount++;
      } else { // incidentEdge is an outEdge
        checkArgument(incidentEdge.nodeU().equals(thisNode));

        N successor = incidentEdge.nodeV();
        V value = successorNodeToValueFn.apply(successor);