* 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);

   * 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 {