async function sendImportantHeartbeatList(socket, monitorID, toUser = false, overwrite = false) {
    const timeLogger = new TimeLogger();

    let list = await R.find("heartbeat", `
        monitor_id = ?
        AND important = 1
        ORDER BY time DESC
        LIMIT 500
    `, [
        monitorID,
    ]);

    timeLogger.print(`[Monitor: ${monitorID}] sendImportantHeartbeatList`);

    if (toUser) {
        io.to(socket.userID).emit("importantHeartbeatList", monitorID, list, overwrite);
    } else {
        socket.emit("importantHeartbeatList", monitorID, list, overwrite);
    }

}
Important Heart beat list (aka event list)
@param {Socket} socket Socket.io instance
@param {number} monitorID ID of monitor to send heartbeat history
@param {boolean} toUser  True = send to all browsers with the same user id, False = send to the current browser only
@param {boolean} overwrite Overwrite client-side's heartbeat list
@returns {Promise<void>}