* @since 14.0 (since 12.0 as {@code toImmutableSet()}).
   */
  @SuppressWarnings("nullness") // Unsafe, but we can't do much about it now.
  public final ImmutableSet<@NonNull E> toSet() {
    return ImmutableSet.copyOf((Iterable<@NonNull E>) getDelegate());
  }

  /**
   * Returns an {@code ImmutableSortedSet} containing all of the elements from this {@code

   * @since 14.0 (since 12.0 as {@code toImmutableSet()}).
   */
  @SuppressWarnings("nullness") // Unsafe, but we can't do much about it now.
  public final ImmutableSet<@NonNull E> toSet() {
    return ImmutableSet.copyOf((Iterable<@NonNull E>) getDelegate());
  }

  /**
   * Returns an {@code ImmutableSortedSet} containing all of the elements from this {@code