toJSON() {
        return {
            monitorID: this._monitorId,
            status: this._status,
            time: this._time,
            msg: this._msg,
            ping: this._ping,
            important: this._important,
            duration: this._duration,
            retries: this._retries,
        };
    }
Return an object that ready to parse to JSON
@returns {object} Object ready to parse