*/
  private transient int @Nullable [] predecessor;

  /**
   * Pointer to the successor of an entry in insertion order. ENDPOINT indicates a node is the last
   * node in insertion order; all values at indices ≥ {@link #size()} are UNSET.
   */
  private transient int @Nullable [] successor;

  /** Pointer to the first node in the linked list, or {@code ENDPOINT} if there are no entries. */

  /**
   * Remove {@code node} from the set of successors. Returns the value previously associated with
   * the edge connecting the two nodes.
   */
  @CanIgnoreReturnValue
  @Nullable V removeSuccessor(N node);

  /**
   * Add {@code node} as a predecessor to the origin node. In the case of an undirected graph, it
   * also becomes a successor. Associates {@code value} with the edge connecting the two nodes.
   */

  @CanIgnoreReturnValue
  N removeOutEdge(E edge);

  /**
   * Add {@code edge} to the set of incoming edges. Implicitly adds {@code node} as a predecessor.
   */
  void addInEdge(E edge, N node, boolean isSelfLoop);

  /** Add {@code edge} to the set of outgoing edges. Implicitly adds {@code node} as a successor. */
  void addOutEdge(E edge, N node);

                      Iterators.transform(
                          // filter out 'node' from successors (already covered by predecessors,
                          // above)
                          Sets.difference(graph.successors(node), ImmutableSet.of(node)).iterator(),
                          (N successor) -> EndpointPair.ordered(node, successor))));
            } else {
              return Iterators.unmodifiableIterator(

          } else {
            firstException.addSuppressed(throwable)
          }
        }

        val nextPlan = connectResult.nextPlan
        if (nextPlan != null) {
          // Try this plan's successor before deferred plans because it won the race!
          routePlanner.deferredPlans.addFirst(nextPlan)
        }
      }
    } finally {
      cancelInFlightConnects()
    }

    throw firstException!!

 *       order)
 * </ul>
 *
 * <p>{@code ValueGraph}s built by this class also guarantee that each collection-returning accessor
 * returns a <b>(live) unmodifiable view</b>; see <a
 * href="https://github.com/google/guava/wiki/GraphsExplained#accessor-behavior">the external
 * documentation</a> for details.
 *
 * <p>Examples of use:
 *
 * {@snippet :
 * // Building a mutable value graph

 *       order)
 * </ul>
 *
 * <p>{@code Graph}s built by this class also guarantee that each collection-returning accessor
 * returns a <b>(live) unmodifiable view</b>; see <a
 * href="https://github.com/google/guava/wiki/GraphsExplained#accessor-behavior">the external
 * documentation</a> for details.
 *
 * <p>Examples of use:
 *
 * {@snippet :
 * // Building a mutable graph

 *       order)
 * </ul>
 *
 * <p>{@code ValueGraph}s built by this class also guarantee that each collection-returning accessor
 * returns a <b>(live) unmodifiable view</b>; see <a
 * href="https://github.com/google/guava/wiki/GraphsExplained#accessor-behavior">the external
 * documentation</a> for details.
 *
 * <p>Examples of use:
 *
 * {@snippet :
 * // Building a mutable value graph

 * which has a method {@code getChildren()} that retrieves its successors in a graph:
 *
 * {@snippet :
 * someGraphAlgorithm(startNode, MyNode::getChildren);
 * }
 *
 * <p>If you have some other mechanism for returning the successors of a node, or one that doesn't
 * return an {@code Iterable<? extends N>}, then you can use a lambda to perform a more general

  @Override
  public Set<N> successors() {
    return Collections.unmodifiableSet(successorsMultiset().elementSet());
  }

  private Multiset<N> successorsMultiset() {
    Multiset<N> successors = getReference(successorsReference);
    if (successors == null) {
      successors = HashMultiset.create(outEdgeMap.values());
      successorsReference = new SoftReference<>(successors);
    }
    return successors;
  }