@Override
  public boolean hasSeenEvent(EntryEventImpl ev) {
    // [bruce] PRs don't track events - their buckets do that
    if (dataStore == null) {
      return false;
    }
    return dataStore.hasSeenEvent(ev);
  }
Test hook to return the per entry overhead for a bucket region. Returns -1 if no buckets exist
in this vm.

@since GemFire 6.1.2.9
geode-core/src/main/java/org/apache/geode/internal/cache/PartitionedRegion.java