protected function isFreshEnough(Request $request, Response $entry)
    {
        if (!$entry->isFresh()) {
            return $this->lock($request, $entry);
        }

        if ($this->options['allow_revalidate'] && null !== $maxAge = $request->headers->getCacheControlDirective('max-age')) {
            return $maxAge > 0 && $maxAge >= $entry->getAge();
        }

        return true;
    }