private void cancelTTLExpiryTask() {
    RegionTTLExpiryTask task;
    synchronized (regionExpiryLock) {
      task = regionTTLExpiryTask;
      if (task != null) {
        regionTTLExpiryTask = null;
      }
    }
    if (task != null) {
      task.cancel();
    }
  }
Add the Region Idle expiry task to the scheduler
geode-core/src/main/java/org/apache/geode/internal/cache/LocalRegion.java