@Override
      public Object call() throws Exception {
        Map<Object, VersionTag> map = new HashMap<>();
        LocalRegion r = (LocalRegion) getCache().getRegion(regionName);
        Iterator<Object> it = null;
        if (r instanceof PartitionedRegion) {
          Region l = PartitionRegionHelper.getLocalPrimaryData(r);
          it = l.keySet().iterator();
        } else {
          it = r.keySet().iterator();
        }
        while (it.hasNext()) {
          Object key = it.next();
          map.put(key, r.getRegionEntry(key).getVersionStamp().asVersionTag());
        }
        return map;
      }
test client initiated transactions with concurrency checks enabled.
geode-core/src/distributedTest/java/org/apache/geode/internal/cache/ClientServerTransactionCCEDUnitTest.java