async Avg_response_time(from: moment.Moment, to: moment.Moment, departmentId?: string, extraQuery: Filter<IOmnichannelRoom> = {}) {
        const agentAvgRespTime = new Map(); // stores avg response time for each agent
        const date = {
            gte: from.toDate(),
            lt: to.add(1, 'days').toDate(),