implements ScheduledExecutorService {
  final ScheduledExecutorService delegate;

  protected WrappingScheduledExecutorService(ScheduledExecutorService delegate) {
    super(delegate);
    this.delegate = delegate;
  }

  @Override
  public final ScheduledFuture<?> schedule(Runnable command, long delay, TimeUnit unit) {
    return delegate.schedule(wrapTask(command), delay, unit);
  }

  @Override

   *
   * @since 9.0
   */
  public abstract static class SimpleForwardingListenableFuture<V extends @Nullable Object>
      extends ForwardingListenableFuture<V> {
    private final ListenableFuture<V> delegate;

    protected SimpleForwardingListenableFuture(ListenableFuture<V> delegate) {
      this.delegate = Preconditions.checkNotNull(delegate);
    }

    @Override

  }

  @Override
  public final boolean isRunning() {
    return delegate.isRunning();
  }

  @Override
  public final State state() {
    return delegate.state();
  }

  /**
   * @since 13.0
   */
  @Override
  public final void addListener(Listener listener, Executor executor) {
    delegate.addListener(listener, executor);
  }

  /**
   * @since 14.0
   */

  private final transient Set<E> delegate;

  ForwardingImmutableSet(Set<E> delegate) {
    // TODO(cpovirk): are we over-wrapping?
    this.delegate = Collections.unmodifiableSet(delegate);
  }

  @Override
  public UnmodifiableIterator<E> iterator() {
    return Iterators.unmodifiableIterator(delegate.iterator());
  }

  @Override

    // This allows us to only start up a thread waiting on the delegate future when the first
    // listener is added.
    private final AtomicBoolean hasListeners = new AtomicBoolean(false);

    // The delegate future.
    private final Future<V> delegate;

    ListenableFutureAdapter(Future<V> delegate) {
      this(delegate, defaultAdapterExecutor);
    }

      boolean toInclusive) {
    return delegate().subMap(fromKey, fromInclusive, toKey, toInclusive);
  }

  @Override
  public NavigableMap<K, V> headMap(@ParametricNullness K toKey, boolean inclusive) {
    return delegate().headMap(toKey, inclusive);
  }

  @Override
  public NavigableMap<K, V> tailMap(@ParametricNullness K fromKey, boolean inclusive) {
    return delegate().tailMap(fromKey, inclusive);
  }

      boolean toInclusive) {
    return delegate().subMap(fromKey, fromInclusive, toKey, toInclusive);
  }

  @Override
  public NavigableMap<K, V> headMap(@ParametricNullness K toKey, boolean inclusive) {
    return delegate().headMap(toKey, inclusive);
  }

  @Override
  public NavigableMap<K, V> tailMap(@ParametricNullness K fromKey, boolean inclusive) {
    return delegate().tailMap(fromKey, inclusive);
  }

    private final TestMultisetGenerator<E> delegate;

    ForwardingTestMultisetGenerator(TestMultisetGenerator<E> delegate) {
      this.delegate = delegate;
    }

    @Override
    public SampleElements<E> samples() {
      return delegate.samples();
    }

    @Override
    public E[] createArray(int length) {
      return delegate.createArray(length);
    }

    @Override

    @ParametricNullness final K key;
    Collection<V> delegate;
    final @Nullable WrappedCollection ancestor;
    final @Nullable Collection<V> ancestorDelegate;

    WrappedCollection(
        @ParametricNullness K key, Collection<V> delegate, @Nullable WrappedCollection ancestor) {
      this.key = key;
      this.delegate = delegate;
      this.ancestor = ancestor;

  private InvalidatableSet(
      Set<E> delegate, Supplier<Boolean> validator, Supplier<String> errorMessage) {
    this.delegate = delegate;
    this.validator = validator;
    this.errorMessage = errorMessage;
  }

  // Override hashCode() to access delegate directly (so that it doesn't trigger the validate() call
  // via delegate()); it seems inappropriate to throw ISE on this method.
  @Override
  public int hashCode() {