public DistributedRegion getRegionForDeltaGII() {
    if (advisee instanceof DistributedRegion) {
      return (DistributedRegion) advisee;
    }
    return null;
  }
find the region for a delta-gii operation (synch)
geode-core/src/main/java/org/apache/geode/distributed/internal/DistributionAdvisor.java