int fillDrainList() {
    synchronized (getDrainSync()) {
      ForceableLinkedBlockingQueue<Object> queue = getAsyncQueue();
      drainList = new ArrayList<>(queue.size());
      return queue.drainTo(drainList);
    }
  }
This queue can continue DiskEntry of FlushNotifier.
geode-core/src/main/java/org/apache/geode/internal/cache/DiskStoreImpl.java