private function createRevalidationRequest(
        RequestInterface $request,
        ResponseInterface $response
    ) {
        $validate = clone $request;
        $validate->getConfig()->set('cache.disable', true);
        $validate->removeHeader('Pragma');
        $validate->removeHeader('Cache-Control');
        $responseDate = $response->getHeader('Last-Modified')
            ?: $response->getHeader('Date');
        $validate->setHeader('If-Modified-Since', $responseDate);

        if ($etag = $response->getHeader('ETag')) {
            $validate->setHeader('If-None-Match', $etag);
        }

        return $validate;
    }