// value of this type is passed to the `MetricsLoaderFn`.
type MetricValues struct {
	values      map[MetricName][]metricValue
	descriptors map[MetricName]MetricDescriptor
}

func newMetricValues(d map[MetricName]MetricDescriptor) MetricValues {
	return MetricValues{
		values:      make(map[MetricName][]metricValue, len(d)),
		descriptors: d,
	}
}