Future<?> enqueueStoragePagesClosing(final @NotNull PagedFileStorageWithRWLockedPageContent storage,
                                       final @NotNull CompletableFuture<Object> finish) {
    checkNotClosed();
    final PostCloseStorageCleanupCommand task = new PostCloseStorageCleanupCommand(storage, finish);
    commandsQueue.add(task);
    return task.onFinish;
  }
Future<?> enqueueStoragePagesClosing(final @NotNull PagedFileStorageWithRWLockedPageContent storage,
                                       final @NotNull CompletableFuture<Object> finish)