code: public void addNewReporter(ContextAwareReporter reporter) {
      this.reporters.add(this.closer.register(reporter));
      if (this.reportingStarted) {
        reporter.start();
      }
    }
docs: Add a new {@link ContextAwareReporter} to the {@link RootMetricContext} for it to manage.
  @param reporter {@link ContextAwareReporter} to manage.