*/
      seenExceptionsLocal = requireNonNull(seenExceptionsField);
    }
    return seenExceptionsLocal;
  }

  /** Populates {@code seen} with the exception that was passed to {@code setException}. */
  abstract void addInitialException(Set<Throwable> seen);

  final int decrementRemainingAndGet() {
    return ATOMIC_HELPER.decrementAndGetRemainingCount(this);
  }

  final void clearSeenExceptions() {

      for (Entry<E> entry : insertionOrder) {
        map.put(entry.getElement(), entry);
      }

      Set<E> seen = new HashSet<>();
      List<Entry<E>> order = new ArrayList<>();
      for (E e : gen.order(new ArrayList<E>(map.keySet()))) {
        if (seen.add(e)) {
          order.add(map.get(e));
        }
      }
      return order;
    }
  }

    if (localValue != null & notInstanceOfDelegatingToFuture(localValue)) {
      return getDoneValue(localValue);
    }
    // we delay calling nanoTime until we know we will need to either park or spin
    long endNanos = remainingNanos > 0 ? System.nanoTime() + remainingNanos : 0;
    long_wait_loop:
    if (remainingNanos >= SPIN_THRESHOLD_NANOS) {
      Waiter oldHead = waitersField;

    if (localValue != null & notInstanceOfDelegatingToFuture(localValue)) {
      return getDoneValue(localValue);
    }
    // we delay calling nanoTime until we know we will need to either park or spin
    long endNanos = remainingNanos > 0 ? System.nanoTime() + remainingNanos : 0;
    long_wait_loop:
    if (remainingNanos >= SPIN_THRESHOLD_NANOS) {
      Waiter oldHead = waitersField;

   * range [0, k) and ignore the remaining elements.
   */
  private final @Nullable T[] buffer;
  private int bufferSize;

  /**
   * The largest of the lowest k elements we've seen so far relative to this comparator. If
   * bufferSize ≥ k, then we can ignore any elements greater than this value.
   */
  private @Nullable T threshold;

      for (Entry<E> entry : insertionOrder) {
        map.put(entry.getElement(), entry);
      }

      Set<E> seen = new HashSet<>();
      List<Entry<E>> order = new ArrayList<>();
      for (E e : gen.order(new ArrayList<E>(map.keySet()))) {
        if (seen.add(e)) {
          order.add(map.get(e));
        }
      }
      return order;
    }
  }

     * been intended for something else, so don't clear it.
     */
    boolean restoreInterruptedBit = false;
    int spinCount = 0;
    // Interrupting Cow Says:
    //  ______
    // < Spin >
    //  ------
    //        \   ^__^
    //         \  (oo)\_______
    //            (__)\       )\/\
    //                ||----w |
    //                ||     ||
    Runnable state = get();

    final Map<C, V> seen = factory.get();
    final Iterator<Map<C, V>> mapIterator = backingMap.values().iterator();
    Iterator<Entry<C, V>> entryIterator = emptyIterator();

    @Override
    protected @Nullable C computeNext() {
      while (true) {
        if (entryIterator.hasNext()) {
          Entry<C, V> entry = entryIterator.next();
          if (!seen.containsKey(entry.getKey())) {

  // the "short hash".
  //
  // The `keys`, `values`, and `entries` arrays always have the same size as each other. They can be
  // seen as fields of an imaginary `Entry` object like this:
  //
  // class Entry {
  //    int hash;
  //    Entry next;
  //    K key;
  //    V value;
  // }
  //

      /*
       * If the entry has been removed from the map, we return null, even though that might not be a
       * valid value. That's the best we can do, short of holding a reference to the most recently
       * seen value. And while we *could* do that, we aren't required to: Map.Entry explicitly says
       * that behavior is undefined when the backing map is modified through another API. (It even