}

  @Override
  public SortedMultiset<E> tailMultiset(@ParametricNullness E lowerBound, BoundType boundType) {
    return new TreeMultiset<>(
        rootReference,
        range.intersect(GeneralRange.downTo(comparator(), lowerBound, boundType)),
        header);
  }

  private static final class Reference<T> {
    @CheckForNull private T value;

    @CheckForNull
    public T get() {
      return value;

    final AbstractFuture<V> owner;
    final ListenableFuture<? extends V> future;

    SetFuture(AbstractFuture<V> owner, ListenableFuture<? extends V> future) {
      this.owner = owner;
      this.future = future;
    }

    @Override
    public void run() {
      if (owner.value != this) {

              toElement, BoundType.forBoolean(toInclusive)));
    }

    @Override
    ImmutableSortedSet<C> tailSetImpl(C fromElement, boolean inclusive) {
      return subSet(Range.downTo(fromElement, BoundType.forBoolean(inclusive)));
    }

    @Override
    public boolean contains(@CheckForNull Object o) {
      if (o == null) {
        return false;
      }
      try {

              toElement, BoundType.forBoolean(toInclusive)));
    }

    @Override
    ImmutableSortedSet<C> tailSetImpl(C fromElement, boolean inclusive) {
      return subSet(Range.downTo(fromElement, BoundType.forBoolean(inclusive)));
    }

    @Override
    public boolean contains(@CheckForNull Object o) {
      if (o == null) {
        return false;
      }
      try {