private function considerStatusCodes(array $statusCodes): void
    {
        $this->requestCount += count($statusCodes);

        if ($this->autoShutdown) {
            foreach ($statusCodes as $statusCode) {
                if ($statusCode >= 500 && $statusCode < 600) {
                    $this->flagShutdown('Automatic shutdown following status code: ' . $statusCode);
                    break;
                }
            }
        }
    }