code: func (s *MetricSeries) ValueCSV() string {
  	vals := make([]string, len(s.Value))
  
  	for i := range s.Value {
  		vals[i] = s.Format(s.Value[i])
  	}
  
  	return strings.Join(vals, ",")
  }
docs: // ValueCSV converts the Value field to a CSV string