return
			}
		case "Histogram":
			var zb0004 uint32
			zb0004, bts, err = msgp.ReadMapHeaderBytes(bts)
			if err != nil {
				err = msgp.WrapError(err, "Histogram")
				return
			}
			if z.Histogram == nil {
				z.Histogram = make(map[string]uint64, zb0004)
			} else if len(z.Histogram) > 0 {
				for key := range z.Histogram {
					delete(z.Histogram, key)
				}
			}
			for zb0004 > 0 {

				t.Error("got objects", e.Objects, "want", w.objs)
			}
			if e.Versions != uint64(w.objs) {
				t.Error("got versions", e.Versions, "want", w.objs)
			}
			if e.ObjSizes != w.oSizes {
				t.Error("got histogram", e.ObjSizes, "want", w.oSizes)
			}
		})
	}

	files = []usageTestFile{
		{
			name: "newfolder/afile",
			size: 4,
		},
		{
			name: "newfolder/anotherone",
			size: 1,
		},

		VariableLabels:       make(map[string]string, len(m.VariableLabels)),
		Histogram:            make(map[string]uint64, len(m.Histogram)),
	}
	for k, v := range m.StaticLabels {
		metric.StaticLabels[k] = v
	}
	for k, v := range m.VariableLabels {
		metric.VariableLabels[k] = v
	}
	for k, v := range m.Histogram {
		metric.Histogram[k] = v
	}
	return metric
}

			bucket,
		)

		for k, v := range usageInfo.ObjectSizesHistogram {
			ch <- prometheus.MustNewConstMetric(
				prometheus.NewDesc(
					prometheus.BuildFQName(bucketNamespace, "objects", "histogram"),
					"Total number of objects of different sizes in a bucket",
					[]string{"bucket", "object_size"}, nil),
				prometheus.GaugeValue,
				float64(v),
				bucket,
				k,
			)
		}

		case <-ticker.C:
			ttfbHist.With(prometheus.Labels{"api": obs.label}).Observe(obs.val)
		}
	}

	metrics := getHistogramMetrics(ttfbHist, getBucketTTFBDistributionMD(), false)
	// additional labels for +Inf for all histogram metrics
	if expPoints := len(labels) * (len(histBuckets) + 1); expPoints != len(metrics) {
		t.Fatalf("Expected %v data points but got %v", expPoints, len(metrics))
	}

	CounterMT MetricType = iota
	// GaugeMT - represents a gauge metric.
	GaugeMT
	// HistogramMT - represents a histogram metric.
	HistogramMT
)

func (mt MetricType) String() string {
	switch mt {
	case CounterMT:
		return "counter"
	case GaugeMT:
		return "gauge"
	case HistogramMT:
		return "histogram"
	default:
		return "*unknown*"
	}
}

func (mt MetricType) toProm() prometheus.ValueType {

// dataUsageHash is the hash type used.
type dataUsageHash string

// sizeHistogramV1 is size histogram V1, which has fewer intervals esp. between
// 1024B and 1MiB.
type sizeHistogramV1 [dataUsageBucketLenV1]uint64

// sizeHistogram is a size histogram.
type sizeHistogram [dataUsageBucketLen]uint64

// versionsHistogram is a histogram of number of versions in an object.
type versionsHistogram [dataUsageVersionLen]uint64

	ReplicatedCount         uint64 `json:"objectsReplicatedCount"`
}

// BucketUsageInfo - bucket usage info provides
// - total size of the bucket
// - total objects in a bucket
// - object size histogram per bucket
type BucketUsageInfo struct {
	Size uint64 `json:"size"`
	// Following five fields suffixed with V1 are here for backward compatibility
	// Total Size for objects that have not yet been replicated

	{"GREATER_THAN_512_MB", humanize.MiByte * 512, math.MaxInt64},
}

// ObjectsHistogramIntervals is the list of all intervals
// of object sizes to be included in objects histogram.
// Note: this histogram expands 1024B-1MB to incl. 1024B-64KB, 64KB-256KB, 256KB-512KB and 512KB-1MiB
var ObjectsHistogramIntervals = [dataUsageBucketLen]objectHistogramInterval{
	{"LESS_THAN_1024_B", 0, humanize.KiByte - 1},

	}
}

// InQueueStats holds queue stats for replication
type InQueueStats struct {
	nowBytes   int64 `json:"-"`
	nowCount   int64 `json:"-"`
	histCounts metrics.Histogram
	histBytes  metrics.Histogram
}

func newInQueueStats(r metrics.Registry, lbl string) InQueueStats {
	histCounts := metrics.NewHistogram(metrics.NewUniformSample(100))