getFeedIdsToRefresh example

  // Delete all expired records since the last cron run.   $expires = \Drupal::state()->get('mymodule.last_check', 0);
  $request_time = \Drupal::time()->getRequestTime();
  \Drupal::database()->delete('mymodule_table')
    ->condition('expires', $expires, '>=')
    ->execute();
  \Drupal::state()->set('mymodule.last_check', $request_time);

  // Long-running operation example, leveraging a queue:   // Queue news feeds for updates once their refresh interval has elapsed.   $queue = \Drupal::queue('mymodule.feeds');
  $ids = \Drupal::entityTypeManager()->getStorage('mymodule_feed')->getFeedIdsToRefresh();
  foreach (Feed::loadMultiple($ids) as $feed) {
    if ($queue->createItem($feed)) {
      // Add timestamp to avoid queueing item more than once.       $feed->setQueuedTime($request_time);
      $feed->save();
    }
  }
  $ids = \Drupal::entityQuery('mymodule_feed')
    ->accessCheck(FALSE)
    ->condition('queued', $request_time - (3600 * 6), '<')
    ->execute();