@VisibleForTesting @CheckForNull transient @Nullable Object[] elements;

  /**
   * Keeps track of metadata like the number of hash table bits and modifications of this data
   * structure (to make it possible to throw ConcurrentModificationException in the iterator). Note
   * that we choose not to make this volatile, so we do less of a "best effort" to track such
   * errors, for better performance.
   */
  private transient int metadata;

   *
   * <p>This class is accessible but not supported in GWT as it references {@link
   * PermittedMetaException}.
   */
  protected final class MultiExceptionListIterator implements ListIterator<E> {
    // TODO: track seen elements when order isn't guaranteed
    // TODO: verify contents afterward
    // TODO: something shiny and new instead of Stack
    // TODO: test whether null is supported (create a Feature)
    /**

  }

  /**
   * A {@code LockGraphNode} associated with each lock instance keeps track of the directed edges in
   * the lock acquisition graph.
   */
  private static class LockGraphNode {

    /**
     * The map tracking the locks that are known to be acquired before this lock, each associated
     * with an example stack trace. Locks are weakly keyed to allow proper garbage collection when
     * they are no longer referenced.

  /**
   * Returns the number of edges in this graph; used to calculate the size of {@link Graph#edges()}.
   * This implementation requires O(|N|) time. Classes extending this one may manually keep track of
   * the number of edges as the graph is updated, and override this method for better performance.
   */
  protected long edgeCount() {
    long degreeSum = 0L;
    for (N node : nodes()) {

  Set<V> createCollection() {
    return Platform.newLinkedHashSetWithExpectedSize(valueSetCapacity);
  }

  /**
   * {@inheritDoc}
   *
   * <p>Creates a decorated insertion-ordered set that also keeps track of the order in which
   * key-value pairs are added to the multimap.
   *
   * @param key key to associate with values in the collection
   * @return a new decorated set containing a collection of values for one key

    // NOTE: If we ever want to use a custom executor here, have a look at CombinedFuture as we'll
    // need to handle RejectedExecutionException

    if (allMustSucceed) {
      // We need fail fast, so we have to keep track of which future failed so we can propagate
      // the exception immediately

      // Register a listener on each Future in the list to update the state of this future.

   *
   * <p>This class is accessible but not supported in GWT as it references {@link
   * PermittedMetaException}.
   */
  protected final class MultiExceptionListIterator implements ListIterator<E> {
    // TODO: track seen elements when order isn't guaranteed
    // TODO: verify contents afterward
    // TODO: something shiny and new instead of Stack
    // TODO: test whether null is supported (create a Feature)
    /**

   * - System.nanoTime() is expensive enough that we want to call it the minimum required number of
   *   times, typically once before invoking a blocking method. This often requires keeping track of
   *   the first time in a method that nanoTime() has been invoked, for which the special value 0L
   *   is reserved to mean "uninitialized". If timeout is non-positive, then nanoTime need never be
   *   called.

    return stringWriter.toString();
  }

  /**
   * Returns the stack trace of {@code throwable}, possibly providing slower iteration over the full
   * trace but faster iteration over parts of the trace. Here, "slower" and "faster" are defined in
   * comparison to the normal way to access the stack trace, {@link Throwable#getStackTrace()

    return stringWriter.toString();
  }

  /**
   * Returns the stack trace of {@code throwable}, possibly providing slower iteration over the full
   * trace but faster iteration over parts of the trace. Here, "slower" and "faster" are defined in
   * comparison to the normal way to access the stack trace, {@link Throwable#getStackTrace()