code: protected String getMetricNamePrefix(Map<String, Object> tags){
      String currentContextName = (String) tags.get(MetricContext.METRIC_CONTEXT_NAME_TAG_NAME);
      if (metricContextName == null || (currentContextName.indexOf(metricContextName) > -1)) {
        return currentContextName;
      }
  
      return JOINER.join(Strings.emptyToNull(metricsPrefix),
              metricContextName, tags.get("taskId"), tags.get("forkBranchName"), tags.get("class"));
    }
docs: Constructs the prefix of metric key to be emitted.
  Enriches {@link ConfiguredScheduledReporter#metricContextName} with the current task id and fork id to
  be able to identify the emitted metric by its origin
  
  @param tags
  @return Prefix of the metric key