public function getKey(array $params): string
    {
        // Push current options to the list of
        // params to ensure unique cache key for
        // each set of options.
        $params[] = $this->options;

        $params = json_encode($params);
        $params = $params ?: microtime();
        $params = md5($params);

        $result = $this->name . '_' . $params;

        return $result;
    }