assertEquals("Should be able to peek() at first element", "A", peekingIterator.peek());
    assertEquals(
        "Should be able to peek() first element multiple times", "A", peekingIterator.peek());
    assertEquals(
        "next() should still return first element after peeking", "A", peekingIterator.next());

    assertEquals("Should be able to peek() at middle element", "B", peekingIterator.peek());

          }
        };
    AssertionError actual = null;
    try {
      tester.test();
    } catch (AssertionError e) {
      actual = e;
    }
    assertNotNull("verify() should be able to cause test failure", actual);
    assertTrue(
        "AssertionError should have info about why test failed",
        actual.getCause().getMessage().contains(message));
  }

  public void testMissingException() {

         * Breaking AtomicReferenceFieldUpdater not only forces AggregateFutureState to fall back to
         * another implementation but also forces AbstractFutureState to be able to do the
         * same—hence the try-catch here.
         *
         * (Really, we're fortunate that breaking AtomicReferenceFieldUpdater doesn't break _even
         * more_ things.)
         */

      extends UnsupportedOperationException {
    // Package-private because this should only be thrown by loadAll() when it is not overridden.
    // Cache implementors may want to catch it but should not need to be able to throw it.
    UnsupportedLoadingOperationException() {}
  }

  /**
   * Thrown to indicate that an invalid response was returned from a call to {@link CacheLoader}.
   *
   * @since 11.0
   */

   *     the size method
   */
  public static <T extends @Nullable Object> Collection<T> misleadingSizeCollection(int delta) {
    // It would be nice to be able to return a real concurrent
    // collection like ConcurrentLinkedQueue, so that e.g. concurrent
    // iteration would work, but that would not be GWT-compatible.

   * apply to {@code getAnnotatedBounds()}. This does mean that users on Java who obtain an instance
   * of {@code TypeVariable} from {@link TypeResolver#resolveType} will not be able to call {@code
   * getAnnotatedBounds()} on it, but that should hopefully be rare.
   *
   * <p>TODO: b/147144588 - We are currently also missing the methods inherited from {@link

 * explanation.
 *
 * @param <K> the most general key type this builder will be able to create caches for. This is
 *     normally {@code Object} unless it is constrained by using a method like {@link
 *     #removalListener}. Cache keys may not be null.
 * @param <V> the most general value type this builder will be able to create caches for. This is
 *     normally {@code Object} unless it is constrained by using a method like {@link

   * apply to {@code getAnnotatedBounds()}. This does mean that users on Java who obtain an instance
   * of {@code TypeVariable} from {@link TypeResolver#resolveType} will not be able to call {@code
   * getAnnotatedBounds()} on it, but that should hopefully be rare.
   *
   * <p>TODO: b/147144588 - We are currently also missing the methods inherited from {@link

  /*
   * The following fields are package-private, even though we intend never to use them outside this
   * file. If they were instead private, then we wouldn't be able to access them reflectively from
   * within VarHandleAtomicHelper and AtomicReferenceFieldUpdaterAtomicHelper.
   *
   * Package-private "shouldn't" be necessary: The *AtomicHelper classes and AbstractFutureState

    //
    // Except for (c), every thread should occupy the monitor very briefly, and every thread leaves
    // the monitor with the guard satisfied. Therefore as soon as tearDownLatch is triggered, we
    // should be able to enter the monitor, and then we set the guard to satisfied for the benefit
    // of any remaining waiting threads.

    tearDownLatch.countDown();
    assertTrue(
        "Monitor still occupied in tearDown()",