Contao\CoreBundle\EventListener\MergeHttpHeadersListener::mergeHttpHeaders PHP Method

    private function mergeHttpHeaders(Response $response)
    {
        foreach ($this->getHeaders() as $header) {
            list($name, $content) = explode(':', $header, 2);
            if ('cli' !== PHP_SAPI) {
                header_remove($name);
            }
            $uniqueKey = $this->getUniqueKey($name);
            if (in_array($uniqueKey, $this->multiHeaders)) {
                $response->headers->set($uniqueKey, trim($content), false);
            } elseif (!$response->headers->has($uniqueKey)) {
                $response->headers->set($uniqueKey, trim($content));
            }
        }
        return $response;
    }