private long oplogSize() {
    long size = ((LocalRegion) region).getDiskRegion().getDiskStore().undeletedOplogSize.get();
    Oplog[] opArray =
        ((LocalRegion) region).getDiskRegion().getDiskStore().getPersistentOplogs().getAllOplogs();
    if (opArray != null) {
      for (Oplog log : opArray) {
        size += log.getOplogSize();
      }
    }
    return size;
  }
Tests if without rolling the region size before close is same as after recreation
geode-core/src/integrationTest/java/org/apache/geode/internal/cache/OplogJUnitTest.java