ListenableFuture<@Nullable Void> unused = serializer.submit(blockingCallable, executor);
    ListenableFuture<Boolean> future2 =
        serializer.submit(
            new Callable<Boolean>() {
              @Override
              public Boolean call() {
                return blockingCallable.isRunning();
              }
            },
            directExecutor());

    /**
     * Total number of pages.
     */
    private int allPageCount;

    /**
     * Flag indicating if a previous page exists.
     */
    private boolean existPrePage;

    /**
     * Flag indicating if a next page exists.
     */
    private boolean existNextPage;

    /**
     * List of page numbers for pagination.
     */
    private List<Integer> pageNumberList;

    /**

    // Configuration
    private final int maxPathLength;
    private final int maxComponentLength;
    private final boolean allowUncPaths;
    private final boolean strictMode;
    private final Set<String> blacklistedPaths;
    private final Set<String> whitelistedPaths;

    /**
     * Create path validator with default settings
     */

    private final ConcurrentHashMap<String, FileInfo> children;
    private final ReadWriteLock lock;
    
    // Cache metadata
    private volatile boolean isComplete;  // True if full enumeration cached
    private volatile boolean hasChanges;  // True if changes detected
    private DirectoryCacheScope scope;
    private long maxAge;
    

    //                                                                         ===========
    @Override
    public boolean hasPrimaryKey() {
        return false;
    }

    @Override
    public boolean hasCompoundPrimaryKey() {
        return false;
    }

    @Override
    protected UniqueInfo cpui() {
        return null;
    }

    return previousSuccessor == null ? null : (V) previousSuccessor;
  }

  private static boolean isPredecessor(@Nullable Object value) {
    return (value == PRED) || (value instanceof PredAndSucc);
  }

  private static boolean isSuccessor(@Nullable Object value) {
    return (value != PRED) && (value != null);
  }

    @SuppressWarnings("deprecation")
    private static boolean isExternalAuth(CIFSContext tc, NtlmPasswordAuthenticator npa) {
        return npa instanceof jcifs.smb.NtlmPasswordAuthentication && ((NtlmPasswordAuthentication) npa).areHashesExternal()
                && tc.getConfig().getDefaultPassword() != null;
    }

    boolean logoff(boolean inError, boolean inUse) {
        boolean wasInUse = false;

        @Override
        public void refresh() throws CIFSException {
            // no-op for tests
        }

        @Override
        public boolean isGuest() {
            return false; // not guest for test purposes
        }

        @Override
        public boolean isAnonymous() {
            return false; // not anonymous for test purposes
        }

        @Override
        public String getUserDomain() {

 */
final class InvalidatableSet<E> extends ForwardingSet<E> {
  private final Supplier<Boolean> validator;
  private final Set<E> delegate;
  private final Supplier<String> errorMessage;

  static <E> InvalidatableSet<E> of(
      Set<E> delegate, Supplier<Boolean> validator, Supplier<String> errorMessage) {
    return new InvalidatableSet<>(

   */
  static <K, V> Entry<K, V>[] removeDuplicates(
      Entry<K, V>[] entries, int n, int newN, IdentityHashMap<Entry<K, V>, Boolean> duplicates) {
    Entry<K, V>[] newEntries = createEntryArray(newN);
    for (int in = 0, out = 0; in < n; in++) {
      Entry<K, V> entry = entries[in];
      Boolean status = duplicates.get(entry);
      // null=>not dup'd; true=>dup'd, first; false=>dup'd, not first
      if (status != null) {