public function actionPdf()
    {
        $this->getSearchCriteria();
        $this->layout = static::BLANK_LAYOUT;
        $this->dataProvider->pagination = false;
        $content = $this->render('pdf', [
            'dataProvider' => $this->dataProvider,
        ]);
        if (isset($_GET['test'])) {
            return $content;
        } else {
            $mpdf = new \mPDF();
            $mpdf->WriteHTML($content);

            Yii::$app->response->getHeaders()->set('Content-Type', 'application/pdf');
            Yii::$app->response->getHeaders()->set('Content-Disposition', 'attachment; filename="' . $this->getCompatibilityId() . '.pdf"');
            return $mpdf->Output($this->getCompatibilityId() . '.pdf', 'S');
        }
    }