@Override
  protected void postDestroyRegion(boolean destroyDiskRegion, RegionEventImpl event) {
    DiskRegion dr = getDiskRegion();
    if (dr != null && destroyDiskRegion) {
      dr.statsClear(this);
    }
    super.postDestroyRegion(destroyDiskRegion, event);
  }
Invoked when a primary bucket is demoted.
geode-core/src/main/java/org/apache/geode/internal/cache/BucketRegion.java