assertSame(valueThree, newFirst.getValueReference().get());
    assertEquals(hashThree, newFirst.getHash());
    assertSame(entryOne, newFirst.getNext());

    // tail (remaining entries are copied in reverse order)
    newFirst = segment.removeEntryFromChain(entryThree, entryOne);
    assertSame(keyTwo, newFirst.getKey());
    assertSame(valueTwo, newFirst.getValueReference().get());

    assertSame(valueThree, newFirst.getValueReference().get());
    assertEquals(hashThree, newFirst.getHash());
    assertSame(entryOne, newFirst.getNext());

    // tail (remaining entries are copied in reverse order)
    newFirst = segment.removeEntryFromChain(entryThree, entryOne);
    assertSame(keyTwo, newFirst.getKey());
    assertSame(valueTwo, newFirst.getValueReference().get());

     * the combiner is almost certain to hold its own reference to the futures, and a real app would
     * hold a reference to the executor and thus to the combiner. What we really care about is that
     * the futures are released once the combiner is done running. But we happen to provide this
     * earlier cleanup at the moment, so we're testing it.
     */
    GcFinalization.awaitClear(future1Ref);
    GcFinalization.awaitClear(future2Ref);

   * eligibility for garbage collection. This should be called every time expireEntries or
   * evictEntry is called (once the lock is released).
   */
  void processPendingNotifications() {
    RemovalNotification<K, V> notification;
    while ((notification = removalNotificationQueue.poll()) != null) {
      try {

     * the combiner is almost certain to hold its own reference to the futures, and a real app would
     * hold a reference to the executor and thus to the combiner. What we really care about is that
     * the futures are released once the combiner is done running. But we happen to provide this
     * earlier cleanup at the moment, so we're testing it.
     */
    GcFinalization.awaitClear(future1Ref);
    GcFinalization.awaitClear(future2Ref);

          forwardCmp = (Comparator) Ordering.natural();
        }
        result = comparator = reverse(forwardCmp);
      }
      return result;
    }

    // If we inline this, we get a javac error.
    private static <T extends @Nullable Object> Ordering<T> reverse(Comparator<T> forward) {
      return Ordering.from(forward).reverse();
    }

    @Override
    @ParametricNullness
    public K firstKey() {

   * eligibility for garbage collection. This should be called every time expireEntries or
   * evictEntry is called (once the lock is released).
   */
  void processPendingNotifications() {
    RemovalNotification<K, V> notification;
    while ((notification = removalNotificationQueue.poll()) != null) {
      try {