Recursive bool

	// ReportNotFound will return errFileNotFound if all disks reports the BaseDir cannot be found.
	ReportNotFound bool

	// FilterPrefix will only return results with given prefix within folder.
	// Should never contain a slash.
	FilterPrefix string

	// ForwardTo will forward to the given object path.
	ForwardTo string

	// Limit the number of returned objects if > 0.
	Limit int

      @CheckForNull T holder = null;

      @Override
      public void accept(@ParametricNullness T t) {
        this.holder = t;
      }

      @Override
      public boolean tryAdvance(Consumer<? super T> action) {
        while (fromSpliterator.tryAdvance(this)) {
          try {
            // The cast is safe because tryAdvance puts a T into `holder`.

    final Map<Path, Holder> modelByPath = new ConcurrentHashMap<>();

    final Map<GAKey, Holder> modelByGA = new ConcurrentHashMap<>();

    public static class Holder {
        private volatile boolean set;
        private volatile Model model;

        Holder() {}

        Holder(Model model) {
            this.model = Objects.requireNonNull(model);

  }

  public void testGetAndAdd() {
    Count holder = new Count(20);
    assertEquals(20, holder.get());
    holder.add(1);
    assertEquals(21, holder.get());
  }

  public void testAddAndGet() {
    Count holder = new Count(20);
    assertEquals(21, holder.addAndGet(1));
  }

  public void testGetAndSet() {
    Count holder = new Count(10);
    assertEquals(10, holder.getAndSet(20));
    assertEquals(20, holder.get());

  }

  public void testGetAndAdd() {
    Count holder = new Count(20);
    assertEquals(20, holder.get());
    holder.add(1);
    assertEquals(21, holder.get());
  }

  public void testAddAndGet() {
    Count holder = new Count(20);
    assertEquals(21, holder.addAndGet(1));
  }

  public void testGetAndSet() {
    Count holder = new Count(10);
    assertEquals(10, holder.getAndSet(20));
    assertEquals(20, holder.get());

    bimap.put(Currency.DOLLAR, "dollar");
    assertEquals("dollar", bimap.get(Currency.DOLLAR));
    assertEquals(Currency.DOLLAR, bimap.inverse().get("dollar"));
  }

  public void testCreateFromMap() {
    /* Test with non-empty Map. */
    Map<Currency, String> map =
        ImmutableMap.of(
            Currency.DOLLAR, "dollar",
            Currency.PESO, "peso",

    bimap.put(Currency.DOLLAR, "dollar");
    assertEquals("dollar", bimap.get(Currency.DOLLAR));
    assertEquals(Currency.DOLLAR, bimap.inverse().get("dollar"));
  }

  public void testCreateFromMap() {
    /* Test with non-empty Map. */
    Map<Currency, String> map =
        ImmutableMap.of(
            Currency.DOLLAR, "dollar",
            Currency.PESO, "peso",

    bimap.put(Currency.DOLLAR, Country.CANADA);
    assertEquals(Country.CANADA, bimap.get(Currency.DOLLAR));
    assertEquals(Currency.DOLLAR, bimap.inverse().get(Country.CANADA));
  }

  public void testCreateFromMap() {
    /* Test with non-empty Map. */
    Map<Currency, Country> map =
        ImmutableMap.of(
            Currency.DOLLAR, Country.CANADA,
            Currency.PESO, Country.CHILE,

    bimap.put(Currency.DOLLAR, Country.CANADA);
    assertEquals(Country.CANADA, bimap.get(Currency.DOLLAR));
    assertEquals(Currency.DOLLAR, bimap.inverse().get(Country.CANADA));
  }

  public void testCreateFromMap() {
    /* Test with non-empty Map. */
    Map<Currency, Country> map =
        ImmutableMap.of(
            Currency.DOLLAR, Country.CANADA,
            Currency.PESO, Country.CHILE,

				into.addChild(h)
				// We scanned a folder, optionally send update.
				f.updateCache.deleteRecursive(h)
				f.updateCache.copyWithChildren(&f.newCache, h, folder.parent)
				f.sendUpdate()
			}
		}

		// Transfer existing
		if !into.Compacted {
			for _, folder := range existingFolders {
				h := hashPath(folder.name)
				f.updateCache.copyWithChildren(&f.oldCache, h, folder.parent)
			}