//
// Panics if `labels` is not a list of ordered label name and label value pairs
// or if all labels for the metric are not provided.
func (m *MetricValues) Set(name MetricName, value float64, labels ...string) {
	desc, ok := m.descriptors[name]
	if !ok {
		panic(fmt.Sprintf("metric has no description: %s", name))
	}

	if len(labels)%2 != 0 {
		panic("labels must be a list of ordered key-value pairs")
	}