code: @Override
      public void start() {
          super.start();
          // If disabled we do not create a publisher to graphite but error counts are still collected.
          if(enabled) {
              metricPublishing.start(new GraphiteConfigImpl(host, port, pollintervalseconds, queuesize, sendasrate));
          }
          this.startUpMetric = factory.createStartUpMetric(metricObjects, subsystem, new Timer());
          startUpMetric.start();
      }
docs: Starts the appender by starting a background thread to poll the error counters and publish them to Graphite.
  Multiple instances of this EmitToGraphiteLogbackAppender will only start one background thread.
  This method also starts the heartbeat metric background thread.