/**
   * A value class representing single connection between the origin node and another node.
   *
   * <p>There can be two types of connections (predecessor and successor), which is represented by
   * the two implementations.
   */
  private abstract static class NodeConnection<N> {
    final N node;

    NodeConnection(N node) {
      this.node = checkNotNull(node);
    }

    static final class Pred<N> extends NodeConnection<N> {

    TF_EXCLUSIVE_LOCKS_REQUIRED(fn_body->mu) {
  if (num_opers == -1) {
    for (const Node* node : fn_body->graph.op_nodes()) {
      const auto& iter = input_nodes.find(node);
      if (iter == input_nodes.end()) {
        // This node is not referenced in inputs. Add it to the body.
        body_nodes->push_back(node);
      } else {
        // This node is referenced in inputs. Currently, we place an

   * and updates {@link #successorIterator} to iterate through the successors of {@link #node}.
   */
  final boolean advance() {
    checkState(!successorIterator.hasNext());
    if (!nodeIterator.hasNext()) {
      return false;
    }
    node = nodeIterator.next();
    successorIterator = graph.successors(node).iterator();
    return true;
  }

  /**

      Object target = endpointPair.target();
      return (node.equals(source) && successorsOrEmpty(node).contains(target))
          || (node.equals(target) && predecessorsOrEmpty(node).contains(source));
    } else {
      Set<N> adjacent = graph.adjacentNodes(node);
      Object nodeU = endpointPair.nodeU();
      Object nodeV = endpointPair.nodeV();

      return (node.equals(nodeV) && adjacent.contains(nodeU))

  /**
   * Returns the value associated with the edge connecting the origin node to {@code node}, or null
   * if there is no such edge.
   */
  @Nullable V value(N node);

  /** Remove {@code node} from the set of predecessors. */
  void removePredecessor(N node);

  /**
   * Remove {@code node} from the set of successors. Returns the value previously associated with
   * the edge connecting the two nodes.

            // Node array will be partially filled
            assertEquals((byte) 0xAA, uuid.node[0]);
            assertEquals((byte) 0xBB, uuid.node[1]);
            assertEquals((byte) 0xCC, uuid.node[2]);
            assertEquals((byte) 0xDD, uuid.node[3]);
            assertEquals((byte) 0xEE, uuid.node[4]);
            assertEquals((byte) 0x00, uuid.node[5]); // Missing data defaults to 0
        }

     *         specified dependency node's children and proceed to its next sibling
     */
    boolean enter(@Nonnull Node node);

    /**
     * Ends the visit to the specified dependency node.
     *
     * @param node the dependency node to visit
     * @return <code>true</code> to visit the specified dependency node's next sibling, <code>false</code> to skip the
     *         specified dependency node's next siblings and proceed to its parent

   */
  private void removeNode(Node<K, V> node) {
    if (node.previous != null) {
      node.previous.next = node.next;
    } else { // node was head
      head = node.next;
    }
    if (node.next != null) {
      node.next.previous = node.previous;
    } else { // node was tail
      tail = node.previous;
    }
    if (node.previousSibling == null && node.nextSibling == null) {
      /*

### Node Binaries

filename | sha512 hash
-------- | -----------
[kubernetes-node-linux-amd64.tar.gz](https://dl.k8s.io/v1.14.10/kubernetes-node-linux-amd64.tar.gz) | `3f509a406e2c1c889ad447d37f9f34043d61f7e60f14dad2c6a94980283381695e99d058b6a783423d4c5e742d1d6c0c0e16b049dc2e49b6f203bce7c97da025`

        public Node insertBefore(Node newChild, Node refChild) {
            return null;
        }

        @Override
        public Node replaceChild(Node newChild, Node oldChild) {
            return null;
        }

        @Override
        public Node removeChild(Node oldChild) {
            return null;
        }

        @Override
        public Node appendChild(Node newChild) {