count = vertices.size() + vertices.size() / 2;
        }

        checkEdges(count);
    }

    private void checkEdges(int nEdges) {
        if (incidentEdges == null) {
            incidentEdges = new HashMap<>(nEdges);
        }
        if (excidentEdges == null) {
            excidentEdges = new HashMap<>(nEdges);
        }
    }

      }

      for (E incidentEdge : sanityCheckSet(network.incidentEdges(node))) {
        assertTrue(
            network.inEdges(node).contains(incidentEdge)
                || network.outEdges(node).contains(incidentEdge));
        assertThat(network.edges()).contains(incidentEdge);
        assertThat(network.incidentNodes(incidentEdge)).contains(node);
      }

  /**
   * Returns the count of {@code node}'s {@link #incidentEdges(Object) incident edges}, counting
   * self-loops twice (equivalently, the number of times an edge touches {@code node}).
   *
   * <p>For directed networks, this is equal to {@code inDegree(node) + outDegree(node)}.
   *
   * <p>For undirected networks, this is equal to {@code incidentEdges(node).size()} + (number of
   * self-loops incident to {@code node}).

    }

    @Override
    public Set<EndpointPair<N>> incidentEdges(N node) {
      return new IncidentEdgeSet<N>(this, node) {
        @Override
        public Iterator<EndpointPair<N>> iterator() {
          return Iterators.transform(
              delegate().incidentEdges(node).iterator(),
              edge -> EndpointPair.of(delegate(), edge.nodeV(), edge.nodeU()));
        }

    }

    @Override
    public Set<EndpointPair<N>> incidentEdges(N node) {
      return new IncidentEdgeSet<N>(this, node) {
        @Override
        public Iterator<EndpointPair<N>> iterator() {
          return Iterators.transform(
              delegate().incidentEdges(node).iterator(),
              edge -> EndpointPair.of(delegate(), edge.nodeV(), edge.nodeU()));
        }