}

  @Override
  public NavigableSet<E> tailSet(@ParametricNullness E fromElement, boolean inclusive) {
    return delegate().tailSet(fromElement, inclusive);
  }

  /**
   * A sensible definition of {@link #tailSet(Object)} in terms of the {@link #tailSet(Object,
   * boolean)} method. If you override {@link #tailSet(Object, boolean)}, you may wish to override
   * {@link #tailSet(Object)} to forward to this implementation.
   */

  }

  @Override
  public NavigableSet<E> tailSet(@ParametricNullness E fromElement, boolean inclusive) {
    return delegate().tailSet(fromElement, inclusive);
  }

  /**
   * A sensible definition of {@link #tailSet(Object)} in terms of the {@link #tailSet(Object,
   * boolean)} method. If you override {@link #tailSet(Object, boolean)}, you may wish to override
   * {@link #tailSet(Object)} to forward to this implementation.
   */

    return delegate().subSet(fromElement, toElement);
  }

  @Override
  public SortedSet<E> tailSet(@ParametricNullness E fromElement) {
    return delegate().tailSet(fromElement);
  }

  /**
   * A sensible definition of {@link #contains} in terms of the {@code first()} method of {@link
   * #tailSet}. If you override {@link #tailSet}, you may wish to override {@link #contains} to
   * forward to this implementation.
   *

    return delegate().subSet(fromElement, toElement);
  }

  @Override
  public SortedSet<E> tailSet(@ParametricNullness E fromElement) {
    return delegate().tailSet(fromElement);
  }

  /**
   * A sensible definition of {@link #contains} in terms of the {@code first()} method of {@link
   * #tailSet}. If you override {@link #tailSet}, you may wish to override {@link #contains} to
   * forward to this implementation.
   *

    }

    @Override
    public SortedSet<E> headSet(@ParametricNullness E toElement) {
      return multiset().headMultiset(toElement, OPEN).elementSet();
    }

    @Override
    public SortedSet<E> tailSet(@ParametricNullness E fromElement) {
      return multiset().tailMultiset(fromElement, CLOSED).elementSet();
    }

    @Override
    @ParametricNullness
    public E first() {

  }

  @Override
  public ContiguousSet<C> tailSet(C fromElement) {
    return tailSetImpl(checkNotNull(fromElement), true);
  }

  /**
   * @since 12.0
   */
  @GwtIncompatible // NavigableSet
  @Override
  public ContiguousSet<C> tailSet(C fromElement, boolean inclusive) {
    return tailSetImpl(checkNotNull(fromElement), inclusive);
  }

  /*

    return subSet(fromElement, true, toElement, false);
  }

  @Override
  public SortedSet<E> tailSet(E fromElement) {
    return tailSet(fromElement, true);
  }

  @Override
  public NavigableSet<E> tailSet(E fromElement, boolean inclusive) {
    return new SafeTreeSet<>(delegate.tailSet(checkValid(fromElement), inclusive));
  }

  @Override
  public Object[] toArray() {

    return subSet(fromElement, true, toElement, false);
  }

  @Override
  public SortedSet<E> tailSet(E fromElement) {
    return tailSet(fromElement, true);
  }

  @Override
  public NavigableSet<E> tailSet(E fromElement, boolean inclusive) {
    return new SafeTreeSet<>(delegate.tailSet(checkValid(fromElement), inclusive));
  }

  @Override
  public Object[] toArray() {

      return emptySet(comparator());
    }
    return tailSet(fromElement, fromInclusive).headSet(toElement, toInclusive);
  }

  @Override
  public ImmutableSortedSet<E> tailSet(E fromElement) {
    checkNotNull(fromElement);
    try {
      return unsafeDelegateSortedSet(sortedDelegate.tailSet(fromElement), true);
    } catch (IllegalArgumentException e) {
      return emptySet(comparator());

    }

    @Override
    public SortedSet<E> headSet(@ParametricNullness E toElement) {
      return multiset().headMultiset(toElement, OPEN).elementSet();
    }

    @Override
    public SortedSet<E> tailSet(@ParametricNullness E fromElement) {
      return multiset().tailMultiset(fromElement, CLOSED).elementSet();
    }

    @Override
    @ParametricNullness
    public E first() {