Online, Offline int
}

func newNodesUpDownCache() *cachevalue.Cache[nodesOnline] {
	loadNodesUpDown := func(ctx context.Context) (v nodesOnline, err error) {
		v.Online, v.Offline = globalNotificationSys.GetPeerOnlineCount()
		return v, err
	}
	return cachevalue.NewFromFunc(1*time.Minute,
		cachevalue.Opts{ReturnLastGood: true},
		loadNodesUpDown)
}

type driveIOStatMetrics struct {
	readsPerSec    float64