/**
  * Helper method which triggers the rendering of everything between the
  * opening and the closing tag.
  *
  * @return mixed The finally rendered child nodes.
  * @api
  */
 public function renderChildren()
 {
     if ($this->renderChildrenClosure !== null) {
         $closure = $this->renderChildrenClosure;
         return $closure();
     }
     return $this->viewHelperNode->evaluateChildNodes($this->renderingContext);
 }