syncSuccessesMD                          = NewCounterMD(syncSuccesses, "Number of successful IAM data syncs since server start.")
)

// loadClusterIAMMetrics - `MetricsLoaderFn` for cluster IAM metrics.
func loadClusterIAMMetrics(_ context.Context, m MetricValues, _ *metricsCache) error {
	m.Set(lastSyncDurationMillis, float64(atomic.LoadUint64(&globalIAMSys.LastRefreshDurationMilliseconds)))

			pluginAuthnServiceSuccAvgRttMsMinuteMD,
			pluginAuthnServiceSuccMaxRttMsMinuteMD,
			pluginAuthnServiceTotalRequestsMinuteMD,
			sinceLastSyncMillisMD,
			syncFailuresMD,
			syncSuccessesMD,
		},
		loadClusterIAMMetrics,
	)

	clusterReplicationMG := NewMetricsGroup(replicationCollectorPath,
		[]MetricDescriptor{
			replicationAverageActiveWorkersMD,
			replicationAverageQueuedBytesMD,
			replicationAverageQueuedCountMD,