}
        return pop(stack);
      }

      <E extends @Nullable Object> void push(List<E> stack, E value) {
        stack.add(value);
      }

      <E extends @Nullable Object> E pop(List<E> stack) {
        return stack.remove(stack.size() - 1);
      }
    };

    abstract <T extends @Nullable Object, A extends @Nullable Object, R extends @Nullable Object>

    // TODO: verify contents afterward
    // TODO: something shiny and new instead of Stack
    // TODO: test whether null is supported (create a Feature)
    /**
     * The elements to be returned by future calls to {@code next()}, with the first at the top of
     * the stack.
     */
    final Stack<E> nextElements = new Stack<>();

    /**

                    }
                  },
                  service);
        } else if (i % DIRECT_EXECUTIONS_PER_THREAD == DIRECT_EXECUTIONS_PER_THREAD - 1) {
          // When at max depth, record stack trace depth
          lengthChecks.add(
              serializer.submit(
                  new Callable<Integer>() {
                    @Override
                    public Integer call() {

                    }
                  },
                  service);
        } else if (i % DIRECT_EXECUTIONS_PER_THREAD == DIRECT_EXECUTIONS_PER_THREAD - 1) {
          // When at max depth, record stack trace depth
          lengthChecks.add(
              serializer.submit(
                  new Callable<Integer>() {
                    @Override
                    public Integer call() {

    }
  }

  /**
   * Returns a string containing the result of {@link Throwable#toString() toString()}, followed by
   * the full, recursive stack trace of {@code throwable}. Note that you probably should not be
   * parsing the resulting string; if you need programmatic access to the stack frames, you can call
   * {@link Throwable#getStackTrace()}.
   */
  @GwtIncompatible // java.io.PrintWriter, java.io.StringWriter

    }
  }

  /**
   * Returns a string containing the result of {@link Throwable#toString() toString()}, followed by
   * the full, recursive stack trace of {@code throwable}. Note that you probably should not be
   * parsing the resulting string; if you need programmatic access to the stack frames, you can call
   * {@link Throwable#getStackTrace()}.
   */
  @GwtIncompatible // java.io.PrintWriter, java.io.StringWriter

  public final void addTearDown(TearDown tearDown) {
    synchronized (stack) {
      stack.addFirst(checkNotNull(tearDown));
    }
  }

  /** Causes teardown to execute. */
  public final void runTearDown() {
    List<Throwable> exceptions = new ArrayList<>();
    List<TearDown> stackCopy;
    synchronized (stack) {
      stackCopy = Lists.newArrayList(stack);
      stack.clear();
    }
    for (TearDown tearDown : stackCopy) {

          return Lists.<LockGraphNode>newArrayListWithCapacity(3);
        }
      };

  /**
   * A Throwable used to record a stack trace that illustrates an example of a specific lock
   * acquisition ordering. The top of the stack trace is truncated such that it starts with the
   * acquisition of the lock in question, e.g.
   *
   * <pre>
   * com...ExampleStackTrace: LockB -&gt; LockC

          ImmutableList.of(1, 2),
          ImmutableList.of(3, 5),
          ImmutableList.of(2, 4),
          ImmutableList.of(1, 2, 3, 5, 6, 8, 9));

  /*
   * We have a whole series of abstract test classes that "stack", so e.g. the tests for filtered
   * NavigableSets inherit the tests for filtered Iterables, Collections, Sets, and SortedSets. The
   * actual implementation tests are further down.
   */

  public final void addTearDown(TearDown tearDown) {
    synchronized (stack) {
      stack.addFirst(checkNotNull(tearDown));
    }
  }

  /** Causes teardown to execute. */
  public final void runTearDown() {
    List<Throwable> exceptions = new ArrayList<>();
    List<TearDown> stackCopy;
    synchronized (stack) {
      stackCopy = Lists.newArrayList(stack);
      stack.clear();
    }
    for (TearDown tearDown : stackCopy) {