Neos\Neos\View\TypoScriptView::mergeHttpResponseFromOutput PHP Method

    protected function mergeHttpResponseFromOutput($output, Runtime $typoScriptRuntime)
    {
        if (substr($output, 0, 5) === 'HTTP/') {
            $endOfHeader = strpos($output, "\r\n\r\n");
            if ($endOfHeader !== false) {
                $header = substr($output, 0, $endOfHeader + 4);
                try {
                    $renderedResponse = Response::createFromRaw($header);
                    /** @var Response $response */
                    $response = $typoScriptRuntime->getControllerContext()->getResponse();
                    $response->setStatus($renderedResponse->getStatusCode());
                    foreach ($renderedResponse->getHeaders()->getAll() as $headerName => $headerValues) {
                        $response->setHeader($headerName, $headerValues[0]);
                    }
                    $output = substr($output, strlen($header));
                } catch (\InvalidArgumentException $exception) {
                }
            }
        }
        return $output;
    }