}
    }


    /**
     * {@inheritDoc}
     *
     * @see java.util.Iterator#hasNext()
     */
    @Override
    public boolean hasNext () {
        return this.next != null;
    }


    /**
     * {@inheritDoc}
     *
     * @see java.util.Iterator#next()
     */
    @Override
    public FileEntry next () {
        FileEntry n = this.next;

    }

    @Nullable
    public static Path findRoot(Path topDirectory) {
        requireNonNull(topDirectory, "topDirectory");
        Path rootDirectory =
                ServiceLoader.load(RootLocator.class).iterator().next().findRoot(topDirectory);
        if (rootDirectory != null) {
            return getCanonicalPath(rootDirectory);
        }
        return null;
    }

    @Nonnull

    public E element() {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.element();
    }

    @Override
    public Iterator<E> iterator() {
      // We explicitly don't lock for iterator()
      assertFalse(Thread.holdsLock(mutex));
      return delegate.iterator();
    }

    @Override
    public int size() {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.size();
    }

    }
  }

  /**
   * Returns an iterator over the elements in this queue. The iterator does not return the elements
   * in any particular order. The returned {@code Iterator} is a "weakly consistent" iterator that
   * will never throw {@link ConcurrentModificationException}, and guarantees to traverse elements
   * as they existed upon construction of the iterator, and may (but is not guaranteed to) reflect

    }

    @Override
    public Iterator<E> iterator() {
      return Multisets.elementIterator(multiset().entrySet().iterator());
    }
  }

  /**
   * A sensible definition of {@link #iterator} in terms of {@link #entrySet} and {@link
   * #remove(Object)}. If you override either of these methods, you may wish to override {@link
   * #iterator} to forward to this implementation.
   *
   * @since 7.0

    map.putInstance(String.class, "test");
    assertEquals(TypeToken.of(String.class), map.entrySet().iterator().next().getKey());
    assertEquals("test", map.entrySet().iterator().next().getValue());
    assertThrows(
        UnsupportedOperationException.class, () -> map.entrySet().iterator().next().setValue(1));
  }

  public void testEntrySetToArrayMutationThrows() {
    map.putInstance(String.class, "test");

    List<Object> list = new ArrayList<>();
    assertEmpty(list);
    assertEmpty(
        new Iterable<Object>() {
          @Override
          public Iterator<Object> iterator() {
            return emptyList().iterator();
          }
        });

    list.add("a");
    try {
      assertEmpty(list);
      throw new Error();
    } catch (AssertionFailedError expected) {
    }
    try {

    List<Object> list = new ArrayList<>();
    assertEmpty(list);
    assertEmpty(
        new Iterable<Object>() {
          @Override
          public Iterator<Object> iterator() {
            return emptyList().iterator();
          }
        });

    list.add("a");
    try {
      assertEmpty(list);
      throw new Error();
    } catch (AssertionFailedError expected) {
    }
    try {

   */
  Comparator<? super T> comparator();

  /**
   * Returns an iterator over elements of type {@code T}. The elements are returned in nondecreasing
   * order according to the associated {@link #comparator}.
   */
  @Override
  Iterator<T> iterator();

   */
  Comparator<? super T> comparator();

  /**
   * Returns an iterator over elements of type {@code T}. The elements are returned in nondecreasing
   * order according to the associated {@link #comparator}.
   */
  @Override
  Iterator<T> iterator();