public function render(HierarchyInterface $node = null, $criteria = null, $options = [], $includeNode = null)
    {
        return $this->getMapper()->childrenHierarchy(
            $node, // if node is null starting from root nodes
            null === $criteria ? $this->direct() : $criteria, // true: load all children, false: only direct, array: criteria
            array_replace_recursive($this->getOptions(), $options),
            null === $includeNode ? $this->includeNode() : $includeNode
        );
    }