code: func ReportSysMetrics(reporters []Reporter, period time.Duration) {
  	for {
  		for _, r := range reporters {
  			num := runtime.NumGoroutine()
  			m := &runtime.MemStats{}
  			runtime.ReadMemStats(m)
  
  			r.ReportGauge(Goroutines, map[string]string{}, float64(num))
  			r.ReportGauge(HeapSize, map[string]string{}, float64(m.Alloc))
  			r.ReportGauge(HeapObjects, map[string]string{}, float64(m.HeapObjects))
  		}
  
  		time.Sleep(period)
  	}
  }
docs: // ReportSysMetrics reports sys metrics