private long getSize(PartitionedRegionDataStore ds) {
    long size = 0;
    int totalNumBuckets = ds.getPartitionedRegion().getPartitionAttributes().getTotalNumBuckets();
    for (int i = 0; i < totalNumBuckets; i++) {
      size += ds.getBucketSize(i);
    }
    return size;
  }
Creates partitioned regions in multiple vms and fully exercises the internal-only
getInternalPRDetails API on ResourceManager.
geode-core/src/distributedTest/java/org/apache/geode/cache/management/ResourceManagerDUnitTest.java