// This metric is only used for KMS v1 API.
	dekCacheInterArrivals = metrics.NewHistogramVec(
		&metrics.HistogramOpts{
			Namespace:      namespace,
			Subsystem:      subsystem,
			Name:           "dek_cache_inter_arrival_time_seconds",
			Help:           "Time (in seconds) of inter arrival of transformation requests.",
			StabilityLevel: metrics.ALPHA,
			Buckets:        metrics.ExponentialBuckets(60, 2, 10),
		},