code: func LabelProtosToMetric(labelPairs []*prompb.Label) model.Metric {
  	metric := make(model.Metric, len(labelPairs))
  	for _, l := range labelPairs {
  		metric[model.LabelName(l.Name)] = model.LabelValue(l.Value)
  	}
  	return metric
  }
docs: // LabelProtosToMetric unpack a []*prompb.Label to a model.Metric