Optional<BinaryNode> root = Optional.absent();
        for (int i = 0; i < size; i++) {
          root = Optional.of(new BinaryNode(rng.nextInt(), root, Optional.<BinaryNode>absent()));
        }
        return root;
      }
    },
    ALL_RIGHT {
      @Override
      Optional<BinaryNode> createTree(int size, Random rng) {
        Optional<BinaryNode> root = Optional.absent();

      @Override
      long treeAggregate(@CheckForNull AvlNode<?> root) {
        return (root == null) ? 0 : root.totalCount;
      }
    },
    DISTINCT {
      @Override
      int nodeAggregate(AvlNode<?> node) {
        return 1;
      }

      @Override
      long treeAggregate(@CheckForNull AvlNode<?> root) {
        return (root == null) ? 0 : root.distinctElements;
      }
    };

      return Traverser.forTree((N node) -> getChildren(node)).depthFirstPreOrder(root);
    }
  }

  abstract class TreeTraverserPostOrder<N> {
    @Placeholder
    abstract Iterable<N> getChildren(N node);

    @BeforeTemplate
    Iterable<N> before1(N root) {
      return TreeTraverser.using((N node) -> getChildren(node)).postOrderTraversal(root);
    }

    @BeforeTemplate
    Iterable<N> before2(N root) {

          }
        }.accept(root);
      }
    };
  }

  UnmodifiableIterator<T> postOrderIterator(T root) {
    return new PostOrderIterator(root);
  }

  private static final class PostOrderNode<T> {
    final T root;
    final Iterator<T> childIterator;

    PostOrderNode(T root, Iterator<T> childIterator) {
      this.root = checkNotNull(root);

 */
@GwtCompatible
final class Platform {

  /** Format the template with args, only supports the placeholder {@code %s}. */
  static String format(String template, Object... args) {
    return String.format(Locale.ROOT, template, args);
  }

  /** See {@link ListListIteratorTester} */
  static int listListIteratorTesterNumIterations() {
    return 4;
  }

  /** See {@link CollectionIteratorTester} */

  static void checkCast(Class<?> clazz, Object obj) {
    Object unused = clazz.cast(obj);
  }

  static String format(String template, Object... args) {
    return String.format(Locale.ROOT, template, args);
  }

  private Platform() {}

  static void checkCast(Class<?> clazz, Object obj) {
    Object unused = clazz.cast(obj);
  }

  static String format(String template, Object... args) {
    return String.format(Locale.ROOT, template, args);
  }

  private Platform() {}

    assertLessThan(STOPPING, TERMINATED);
  }

  private static <T extends Comparable<? super T>> void assertLessThan(T a, T b) {
    if (a.compareTo(b) >= 0) {
      fail(String.format(Locale.ROOT, "Expected %s to be less than %s", a, b));
    }
  }

  @Deprecated
  public final FluentIterable<T> preOrderTraversal(final T root) {
    checkNotNull(root);
    return new FluentIterable<T>() {
      @Override
      public UnmodifiableIterator<T> iterator() {
        return preOrderIterator(root);
      }
    };
  }

  UnmodifiableIterator<T> preOrderIterator(T root) {
    return new PreOrderIterator(root);
  }

    }

    @Override
    public void uncaughtException(Thread t, Throwable e) {
      try {
        logger
            .get()
            .log(
                SEVERE,
                String.format(Locale.ROOT, "Caught an exception in %s.  Shutting down.", t),
                e);
      } catch (Throwable errorInLogging) { // sneaky checked exception
        // If logging fails, e.g. due to missing memory, at least try to log the