@Retained(OffHeapIdentifier.TEST_OFF_HEAP_REGION_BASE_LISTENER)
    private void setEventData(EntryEvent e) {
      close();
      EntryEventImpl event = (EntryEventImpl) e;
      ohOldValue = event.getOffHeapOldValue();
      ohNewValue = event.getOffHeapNewValue();
    }
This method retains both ohOldValue and ohNewValue
geode-core/src/integrationTest/java/org/apache/geode/internal/offheap/OffHeapRegionBase.java