code: private void startPollingTask(Config config) {
          Future<?> future;
          PollingTask pollingTask = new PollingTask(config);
  
          future = scheduledExecutor.schedule(pollingTask, config.initialPollDelay, TimeUnit.MILLISECONDS);
  
          pollingFutureRef.getAndSet(future);
      }
docs: Start the polling task.
  
  @param config snapshot of configuration.