public function parse(RequestInterface $request, ResponseInterface $response, MapInterface $attributes) : MapInterface { $start = $this->clock->now(); if (!$response->headers()->has('Content-Language') || !$response->headers()->get('Content-Language') instanceof ContentLanguage) { return $attributes; } return $attributes->put(self::key(), new Attribute(self::key(), $response->headers()->get('Content-Language')->values()->reduce(new Set('string'), function (Set $carry, ContentLanguageValue $language) : Set { return $carry->add((string) $language); }), $this->clock->now()->elapsedSince($start)->milliseconds())); }