// 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
   */

      // 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`.

  }

  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) {

   * 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.
   *

   * 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.
   *
   * @since 21.0
   */

    // Ensure that referenceMap, which doesn't use WithExpectedSize, ends up with the same table
    // size as the other two maps. If it ended up with a smaller size that would imply that we
    // computed the wrong initial capacity.
    for (int i = 0; i < size; i++) {
      referenceMap.put(i, null);
    }
    assertWithMessage("table size after adding " + size + " elements")
        .that(initialBuckets)

    // Ensure that referenceMap, which doesn't use WithExpectedSize, ends up with the same table
    // size as the other two maps. If it ended up with a smaller size that would imply that we
    // computed the wrong initial capacity.
    for (int i = 0; i < size; i++) {
      referenceMap.put(i, null);
    }
    assertWithMessage("table size after adding " + size + " elements")
        .that(initialBuckets)

  }

  @Override
  @CheckForNull
  public V compute(
      K key, BiFunction<? super K, ? super @Nullable V, ? extends @Nullable V> function) {
    checkNotNull(key);
    checkNotNull(function);
    int hash = hash(key);
    return segmentFor(hash).compute(key, hash, function);
  }

  @Override