// data usage has not captured any data yet.
	if dataUsageInfo.LastUpdate.IsZero() {
		return
	}

	for bucket, usageInfo := range dataUsageInfo.BucketsUsage {
		stat := globalReplicationStats.Load().getLatestReplicationStats(bucket)
		// Total space used by bucket
		ch <- prometheus.MustNewConstMetric(
			prometheus.NewDesc(
				prometheus.BuildFQName(bucketNamespace, "usage", "size"),
				"Total bucket size",

	r.mostRecentStats.Timestamp = UTCNow()
	r.mostRecentStatsMu.Unlock()
	return bs
}

// get the most current of in-memory replication stats  and data usage info from crawler.
func (r *ReplicationStats) getLatestReplicationStats(bucket string) (s BucketStats) {
	if r == nil {
		return s
	}
	bucketStats := globalNotificationSys.GetClusterBucketStats(GlobalContext, bucket)
	return r.calculateBucketReplicationStats(bucket, bucketStats)