code: func tagsFromMetric(m model.Metric) map[string]TagValue {
  	tags := make(map[string]TagValue, len(m)-1)
  	for l, v := range m {
  		if l == model.MetricNameLabel {
  			continue
  		}
  		tags[string(l)] = TagValue(v)
  	}
  	return tags
  }
docs: // tagsFromMetric translates Prometheus metric into OpenTSDB tags.