* each appears first in the source collection.
   *
   * <p><b>Performance note:</b> This method will sometimes recognize that the actual copy operation
   * is unnecessary; for example, {@code copyOf(copyOf(anArrayList))} will copy the data only once.
   * This reduces the expense of habitually making defensive copies at API boundaries. However, the

   * each appears first in the source collection.
   *
   * <p><b>Performance note:</b> This method will sometimes recognize that the actual copy operation
   * is unnecessary; for example, {@code copyOf(copyOf(anArrayList))} will copy the data only once.
   * This reduces the expense of habitually making defensive copies at API boundaries. However, the

      default:
        return new RegularImmutableSet<E>(delegate);
    }
  }

  private static <E> ImmutableSet<E> create(E... elements) {
    // Create the set first, to remove duplicates if necessary.
    Set<E> set = Sets.newLinkedHashSet();
    Collections.addAll(set, elements);
    for (E element : set) {
      checkNotNull(element);
    }

    switch (set.size()) {
      case 0: