int remaining = queue.size();
      while (queueIterator.hasNext()) {
        Integer element = queueIterator.next();
        remaining--;
        assertThat(elements).contains(element);
        if (random.nextBoolean()) {
          elements.remove(element);
          queueIterator.remove();
        }
      }
      assertThat(remaining).isEqualTo(0);
      assertIntact(queue);

      int remaining = queue.size();
      while (queueIterator.hasNext()) {
        Integer element = queueIterator.next();
        remaining--;
        assertThat(elements).contains(element);
        if (random.nextBoolean()) {
          elements.remove(element);
          queueIterator.remove();
        }
      }
      assertThat(remaining).isEqualTo(0);
      assertIntact(queue);

      E e1, E e2, E e3, E e4, E e5, E e6, E... remaining) {
    Comparable<?>[] contents = new Comparable<?>[6 + remaining.length];
    contents[0] = e1;
    contents[1] = e2;
    contents[2] = e3;
    contents[3] = e4;
    contents[4] = e5;
    contents[5] = e6;
    arraycopy(remaining, 0, contents, 6, remaining.length);
    return construct(Ordering.natural(), contents.length, (E[]) contents);

      E e1, E e2, E e3, E e4, E e5, E e6, E... remaining) {
    Comparable<?>[] contents = new Comparable<?>[6 + remaining.length];
    contents[0] = e1;
    contents[1] = e2;
    contents[2] = e3;
    contents[3] = e4;
    contents[4] = e5;
    contents[5] = e6;
    arraycopy(remaining, 0, contents, 6, remaining.length);
    return construct(Ordering.natural(), contents.length, (E[]) contents);

   * @param array the array of elements to append
   * @return an array whose size is one larger than {@code array}, with {@code element} occupying
   *     the first position, and the elements of {@code array} occupying the remaining elements.
   */
  public static <T extends @Nullable Object> T[] concat(@ParametricNullness T element, T[] array) {
    T[] result = newArray(array, array.length + 1);
    result[0] = element;

   * @param array the array of elements to append
   * @return an array whose size is one larger than {@code array}, with {@code element} occupying
   *     the first position, and the elements of {@code array} occupying the remaining elements.
   */
  public static <T extends @Nullable Object> T[] concat(@ParametricNullness T element, T[] array) {
    T[] result = newArray(array, array.length + 1);
    result[0] = element;

        .addEqualityGroup(EnumBiMap.create(ImmutableMap.of(Currency.DOLLAR, Country.CHILE)))
        .addEqualityGroup(EnumBiMap.create(ImmutableMap.of(Currency.FRANC, Country.CANADA)))
        .testEquals();
  }

  /* Remaining behavior tested by AbstractBiMapTest. */

  }

  private static final class UnknownElementException extends RuntimeException {
    private UnknownElementException(Collection<?> expected, Object actual) {
      super("Returned value '" + actual + "' not found. Remaining elements: " + expected);
    }

    private static final long serialVersionUID = 0;
  }

  /**
   * Quasi-implementation of {@link ListIterator} that works from a list of elements and a set of

   * We are currently considering the elements in buffer in the range [0, bufferSize) as candidates
   * for the top k elements. Whenever the buffer is filled, we quickselect the top k elements to the
   * range [0, k) and ignore the remaining elements.
   */
  private final @Nullable T[] buffer;
  private int bufferSize;

  /**
   * The largest of the lowest k elements we've seen so far relative to this comparator. If

  public abstract long asLong();

  /**
   * If this hashcode has enough bits, returns {@code asLong()}, otherwise returns a {@code long}
   * value with {@code asBytes()} as the least-significant bytes and {@code 0x00} as the remaining
   * most-significant bytes.
   *
   * @since 14.0 (since 11.0 as {@code Hashing.padToLong(HashCode)})
   */
  public abstract long padToLong();

  /**