this.forward = forward;
  }

  @Override
  public boolean contains(@CheckForNull Object object) {
    return forward.contains(object);
  }

  @Override
  public int size() {
    return forward.size();
  }

  @Override
  public UnmodifiableIterator<E> iterator() {
    return forward.descendingIterator();
  }

  @Override
  ImmutableSortedSet<E> headSetImpl(E toElement, boolean inclusive) {

        new ImmutableMap.Builder<>(mapEntries.size());
    int size = 0;

    for (Entry<? extends K, ? extends Collection<? extends V>> entry : mapEntries) {
      K key = entry.getKey();
      Collection<? extends V> values = entry.getValue();
      ImmutableSet<V> set = valueSet(valueComparator, values);
      if (!set.isEmpty()) {
        builder.put(key, set);
        size += set.size();
      }
    }

    private static final int CHUNK_SIZE = 16;
    private static final long C1 = 0x87c37b91114253d5L;
    private static final long C2 = 0x4cf5ad432745937fL;
    private long h1;
    private long h2;
    private int length;

    Murmur3_128Hasher(int seed) {
      super(CHUNK_SIZE);
      this.h1 = seed;
      this.h2 = seed;
      this.length = 0;
    }

          ImmutableSet.copyOf(QuantilesAlgorithm.values()), ImmutableSet.of(REFERENCE_ALGORITHM));

  private double[] dataset;

  @Override
  protected void setUp() {
    dataset = new double[DATASET_SIZE];
    for (int i = 0; i < DATASET_SIZE; i++) {
      dataset[i] = RNG.nextDouble();
    }
  }

  public void testSingleQuantile_median() {
    double referenceValue = REFERENCE_ALGORITHM.singleQuantile(1, 2, dataset.clone());

  }

  @CollectionSize.Require(absent = CollectionSize.ZERO)
  public void testEquals_otherListWithDifferentElements() {
    ArrayList<E> other = new ArrayList<>(getSampleElements());
    other.set(other.size() / 2, getSubjectGenerator().samples().e3());
    assertFalse(
        "A List should not equal another List containing different elements.",
        getList().equals(other));
  }

  }

  @CollectionSize.Require(absent = CollectionSize.ZERO)
  public void testEquals_otherListWithDifferentElements() {
    ArrayList<E> other = new ArrayList<>(getSampleElements());
    other.set(other.size() / 2, getSubjectGenerator().samples().e3());
    assertFalse(
        "A List should not equal another List containing different elements.",
        getList().equals(other));
  }

      if (!list.isEmpty()) {
        builder.put(key, list);
        size += list.size();
      }
    }

    return new ImmutableListMultimap<>(builder.buildOrThrow(), size);
  }

  ImmutableListMultimap(ImmutableMap<K, ImmutableList<V>> map, int size) {
    super(map, size);
  }

  // views

  /**

    int index = elementSet.indexOf(element);
    return (index >= 0) ? getCount(index) : 0;
  }

  @Override
  public int size() {
    long size = cumulativeCounts[offset + length] - cumulativeCounts[offset];
    return Ints.saturatedCast(size);
  }

  @Override
  public ImmutableSortedSet<E> elementSet() {
    return elementSet;
  }

  @Override

    Collections.sort(values, navigableSet.comparator());

    // some tests assume SEVERAL == 3
    if (values.size() >= 1) {
      a = values.get(0);
      if (values.size() >= 3) {
        b = values.get(1);
        c = values.get(2);
      }
    }
  }

  /** Resets the contents of navigableSet to have elements a, c, for the navigation tests. */

    this.predecessorCount = checkNonNegative(predecessorCount);
    this.successorCount = checkNonNegative(successorCount);
    checkState(
        predecessorCount <= adjacentNodeValues.size()
            && successorCount <= adjacentNodeValues.size());
  }

  static <N, V> DirectedGraphConnections<N, V> of(ElementOrder<N> incidentEdgeOrder) {
    // We store predecessors and successors in the same map, so double the initial capacity.