public function startParent($addParentData = [])
    {
        if (!empty($this->_extendingParent[$this->processingViewFile])) {
            throw new InvalidParamException("Nested startParent() impossible in '{$this->processingViewFile}'");
        }
        $this->_extendingParent[$this->processingViewFile] = true;

        $this->_addParentData[$this->processingViewFile] = $addParentData;

        ob_start(); // for lost all non-block info between startParent...stopParent
        ob_implicit_flush(false);
    }