@Override
      public void run() {

        QueryObserver observer = QueryObserverHolder.setInstance(new IndexTrackingQueryObserver());

        // Create Partition Region
        PartitionAttributesFactory paf = new PartitionAttributesFactory();
        paf.setTotalNumBuckets(NUM_BKTS);
        AttributesFactory af = new AttributesFactory();
        af.setPartitionAttributes(paf.create());

        Region region = getCache().createRegion("portfolio", af.create());

      }
CReates a PR on a VM with NUM_BKTS buckets.
geode-core/src/distributedTest/java/org/apache/geode/cache/query/internal/index/IndexTrackingQueryObserverDUnitTest.java