// synchronization used internally.
		select {
		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))

		Subsystem: ttfbSubsystem,
		Name:      ttfbDistribution,
		Help:      "Distribution of time to first byte across API calls",
		Type:      gaugeMetric,
	}
}

func getBucketTTFBDistributionMD() MetricDescription {
	return MetricDescription{
		Namespace: bucketMetricNamespace,
		Subsystem: ttfbSubsystem,
		Name:      ttfbDistribution,