}
        }.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);

    }

    /**
     * Constructs a new TransportException with the specified root cause.
     *
     * @param rootCause the root cause of this exception
     */
    public TransportException(final Throwable rootCause) {
        this.rootCause = rootCause;
    }

    /**
     * Constructs a new TransportException with the specified detail message and root cause.
     *
     * @param msg the detail message

        RequestTrace root = new RequestTrace("root", null, "root-data");
        RequestTrace level1 = new RequestTrace("level1", root, "level1-data");
        RequestTrace level2 = new RequestTrace("level2", level1, "level2-data");
        RequestTrace level3 = new RequestTrace(level2, "level3-data");

        // Verify the chain
        assertNull(root.parent());
        assertEquals(root, level1.parent());

                    request.setPath(dunc);
                }

                if (!t.getShare().equals(dr.getShare())) {
                    // this should only happen for standalone roots or if the DC/domain root lookup failed
                    IOException last;
                    final DfsReferralData start = dr;
                    do {
                        if (log.isDebugEnabled()) {

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

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

        void testGetRootCause() {
            Exception rootCause = new IllegalStateException("Test root cause");
            TransportException exception = new TransportException("Message", rootCause);

            assertEquals(rootCause, exception.getRootCause());
        }

        @Test
        @DisplayName("Should return null when no root cause")
        void testGetRootCauseWhenNull() {

  @Deprecated
  public final FluentIterable<T> preOrderTraversal(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);
  }

    }

    /**
     * Verify that the message + rootCause constructor stores the root.
     */
    @Test
    @DisplayName("Message + root cause stores root cause")
    void testStringAndThrowableConstructor() {
        Throwable root = mock(Throwable.class);
        SmbException ex = new SmbException("oops", root);
        assertSame(root, ex.getRootCause());
    }

    /**

     * root.
     *
     * @return the string if operation succeeded, {@code null} if source does not exist.
     * @throws RuntimeException If failed (and not due source not exists).
     */
    @Nonnull
    Optional<String> getString(@Nonnull URI relativeSource, @Nonnull Charset charset);

    /**
     * GETs the source URI content as string using UTF8 charset. The source MUST BE relative from the
     * {@link RemoteRepository#getUrl()} root.

        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();