code: public static Stream<String> wavefrontLine(DateTime ts, TimeSeriesValue tsv) {
          final GroupName group = tsv.getGroup();
  
          return tsv.getMetrics().entrySet().stream()
                  .flatMap(metricEntry -> wavefrontLineForMetric(ts, group, metricEntry));
      }
docs: Convert a time series value into the string entries for wavefront.
  
  Note: the line is not terminated with a newline.