}
    return totalSize;
  }

  /**
   * Peeks into the cache's internals to check its internal consistency. Verifies that each
   * segment's count matches its #elements (after cleanup), each segment is unlocked, each entry
   * contains a non-null key and value, and the eviction and expiration queues are consistent (see
   * {@link #checkEviction}, {@link #checkExpiration}).
   */
  static void checkValidState(Cache<?, ?> cache) {

  }

  /**
   * Creates a function that returns the same boolean output as the given predicate for all inputs.
   *
   * <p>The returned function is <i>consistent with equals</i> (as documented at {@link
   * Function#apply}) if and only if {@code predicate} is itself consistent with equals.
   *
   * <p><b>Java 8+ users:</b> use the method reference {@code predicate::test} instead.
   */

      assertTrue(item + " must be equivalent to itself", equivalence.equivalent(item, item));
      assertEquals(
          "the hash of " + item + " must be consistent",
          equivalence.hash(item),
          equivalence.hash(item));
    }
  }

   * without grabbing the lock.
   *
   * <p>To update this field correctly the lock must be held to guarantee that the state is
   * consistent.
   */
  private volatile StateSnapshot snapshot = new StateSnapshot(NEW);

  /** Constructor for use by subclasses. */
  protected AbstractService() {}

  /**

    }
    return totalSize;
  }

  /**
   * Peeks into the cache's internals to check its internal consistency. Verifies that each
   * segment's count matches its #elements (after cleanup), each segment is unlocked, each entry
   * contains a non-null key and value, and the eviction and expiration queues are consistent (see
   * {@link #checkEviction}, {@link #checkExpiration}).
   */
  static void checkValidState(Cache<?, ?> cache) {

          !item.equals(NotAnInstance.EQUAL_TO_NOTHING));
      assertTrue(item + " must be Object#equals to itself", item.equals(item));
      assertEquals(
          "the Object#hashCode of " + item + " must be consistent",
          item.hashCode(),
          item.hashCode());
      if (!(item instanceof String)) {
        assertTrue(
            item + " must not be Object#equals to its Object#toString representation",

   * copy.
   *
   * <p><b>Warning:</b> {@code keyPredicate} must be <i>consistent with equals</i>, as documented at
   * {@link Predicate#apply}. Do not provide a predicate such as {@code
   * Predicates.instanceOf(ArrayList.class)}, which is inconsistent with equals.
   *
   * @since 11.0
   */

   * <p>The {@code hash} has the following properties:
   *
   * <ul>
   *   <li>It is <i>consistent</i>: for any reference {@code x}, multiple invocations of {@code
   *       hash(x}} consistently return the same value provided {@code x} remains unchanged
   *       according to the definition of the equivalence. The hash need not remain consistent from
   *       one execution of an application to another execution of the same application.

   *
   * <p>The {@code hash} has the following properties:
   *
   * <ul>
   *   <li>It is <i>consistent</i>: for any reference {@code x}, multiple invocations of {@code
   *       hash(x}} consistently return the same value provided {@code x} remains unchanged
   *       according to the definition of the equivalence. The hash need not remain consistent from
   *       one execution of an application to another execution of the same application.

 *
 * <p>Each of the {@code standard} methods uses the set's comparator (or the natural ordering of the
 * elements, if there is no comparator) to test element equality. As a result, if the comparator is
 * not consistent with equals, some of the standard implementations may violate the {@code Set}
 * contract.
 *
 * <p>The {@code standard} methods and the collection views they return are not guaranteed to be