return topDown(startNodes, InsertionOrder.FRONT);
    }

    /**
     * In top-down traversal, an ancestor node is always traversed before any of its descendant
     * nodes. The traversal order among descendant nodes (particularly aunts and nieces) are
     * determined by the {@code InsertionOrder} parameter: nieces are placed at the FRONT before

  }

  /**
   * Utility for remove and iterator.remove: Delete item at position i. Call only when occupying
   * monitor.
   */
  void removeAt(int i) {
    final E[] items = this.items;
    // if removing front item, just advance
    if (i == takeIndex) {
      items[takeIndex] = null;
      takeIndex = inc(takeIndex);
    } else {
      // slide over all others up through putIndex.
      for (; ; ) {

  }

  /**
   * Utility for remove and iterator.remove: Delete item at position i. Call only when occupying
   * monitor.
   */
  void removeAt(int i) {
    final E[] items = this.items;
    // if removing front item, just advance
    if (i == takeIndex) {
      items[takeIndex] = null;
      takeIndex = inc(takeIndex);
    } else {
      // slide over all others up through putIndex.
      for (; ; ) {