/** * @param Request $request * @param array $output */ private function setHeaderOutput(Request $request, array &$output) { $request->addOption(CURLOPT_HEADERFUNCTION, function ($handle, $headerString) use(&$output) { $header = trim($headerString, "\r\n"); if (strlen($header) > 0) { $output[] = $header; } return mb_strlen($headerString, '8bit'); }); }