// Because Supplier is read-heavy, we use the "double-checked locking" pattern.
      if (delegate != SUCCESSFULLY_COMPUTED) {
        synchronized (this) {
          if (delegate != SUCCESSFULLY_COMPUTED) {
            T t = delegate.get();
            value = t;
            delegate = (Supplier<T>) SUCCESSFULLY_COMPUTED;
            return t;
          }
        }
      }
      // This is safe because we checked `delegate`.

   * the information of these hash codes in an ordered fashion. That is, whenever two equal hash
   * codes are produced by two calls to this method, it is <i>as likely as possible</i> that each
   * was computed from the <i>same</i> input hash codes in the <i>same</i> order.
   *
   * @throws IllegalArgumentException if {@code hashCodes} is empty, or the hash codes do not all
   *     have the same bit length
   */

  }

  public void testHashCodeForBooleanOperations() {
    Predicate<@Nullable Integer> p1 = Predicates.isNull();
    Predicate<@Nullable Integer> p2 = isOdd();

    // Make sure that hash codes are not computed per-instance.
    assertEqualHashCode(Predicates.not(p1), Predicates.not(p1));

    assertEqualHashCode(Predicates.and(p1, p2), Predicates.and(p1, p2));

      }
    }
  }

  /**
   * Returns the expected number of distinct elements given the specified elements. The number of
   * distinct elements is only computed if {@code elements} is an instance of {@code Multiset};
   * otherwise the default value of 11 is returned.
   */
  static int inferDistinctElements(Iterable<?> elements) {
    if (elements instanceof Multiset) {

    for (E element : getOrderedElements()) {
      expectedHashCode = 31 * expectedHashCode + ((element == null) ? 0 : element.hashCode());
    }
    assertEquals(
        "A List's hashCode() should be computed from those of its elements.",
        expectedHashCode,
        getList().hashCode());
  }

  /**
   * Returns the {@link Method} instance for {@link #testHashCode()} so that list tests on

   * values are merged using the specified merging function. If the merging function returns {@code
   * null}, then the collector removes the value that has been computed for the key thus far (though
   * future occurrences of the key would reinsert it).
   *
   * <p>Entries will appear in the encounter order of the first occurrence of the key.
   *

    // Compute the filter.
    long filter = 0;
    int size = chars.cardinality();
    boolean containsZero = chars.get(0);
    // Compute the hash table.
    char[] table = new char[chooseTableSize(size)];
    int mask = table.length - 1;
    for (int c = chars.nextSetBit(0); c != -1; c = chars.nextSetBit(c + 1)) {
      // Compute the filter at the same time.
      filter |= 1L << c;

  }

  /**
   * Splits {@code sequence} into string components and makes them available through an {@link
   * Iterator}, which may be lazily evaluated. If you want an eagerly computed {@link List}, use
   * {@link #splitToList(CharSequence)}. Java 8+ users may prefer {@link #splitToStream} instead.
   *
   * @param sequence the sequence of characters to split

    T extends @Nullable Object, A extends @Nullable Object, R extends @Nullable Object> {
  /**
   * Creates a {@code CollectorTester} for the specified {@code Collector}. The result of the {@code
   * Collector} will be compared to the expected value using {@link Object#equals}.
   */
  public static <T extends @Nullable Object, A extends @Nullable Object, R extends @Nullable Object>
      CollectorTester<T, A, R> of(Collector<T, A, R> collector) {

   *
   * <p><i>Notes:</i> This is an implementation of the algorithm for Lexicographical Permutations
   * Generation, described in Knuth's "The Art of Computer Programming", Volume 4, Chapter 7,
   * Section 7.2.1.2. The iteration order follows the lexicographical order. This means that the
   * first permutation will be in ascending order, and the last will be in descending order.
   *