static async renderRSS(statusPage, slug) {
        const { heartbeats, statusDescription } = await StatusPage.getRSSPageData(statusPage);

        let proto = config.isSSL ? "https" : "http";
        let host = `${proto}://${config.hostname || "localhost"}:${config.port}/status/${slug}`;

        const feed = new Feed({
            title: "uptime kuma rss feed",
            description: `current status: ${statusDescription}`,
            link: host,
            language: "en", // optional, used only in RSS 2.0, possible values: http://www.w3.org/TR/REC-html40/struct/dirlang.html#langcodes
            updated: new Date(), // optional, default = today
        });

        heartbeats.forEach(heartbeat => {
            feed.addItem({
                title: `${heartbeat.name} is down`,
                description: `${heartbeat.name} has been down since ${heartbeat.time}`,
                id: heartbeat.monitorID,
                date: new Date(heartbeat.time),
            });
        });

        return feed.rss2();
    }
SSR for RSS feed
@param {statusPage} statusPage object
@param {slug} slug from router
@returns {Promise<string>} the rendered html