code: public synchronized void start() {
          if (monitorActive) {
              return;
          }
          lastTime.set(milliSecondFromNano());
          long localCheckInterval = checkInterval.get();
          // if executor is null, it means it is piloted by a GlobalChannelTrafficCounter, so no executor
          if (localCheckInterval > 0 && executor != null) {
              monitorActive = true;
              monitor = new TrafficMonitoringTask();
              scheduledFuture =
                  executor.schedule(monitor, localCheckInterval, TimeUnit.MILLISECONDS);
          }
      }
docs: Start the monitoring process.