Kevinrob\GuzzleCache\CacheEntry::__sleep PHP Method

    public function __sleep()
    {
        // Stream/Resource can't be serialized... So we copy the content
        if ($this->response !== null) {
            $this->responseBody = (string) $this->response->getBody();
            $this->response->getBody()->rewind();
        }
        return array_keys(get_object_vars($this));
    }