private void clearData(Region region) {
    for (final Object o : region.entrySet()) {
      Region.Entry entry = (Region.Entry) o;
      region.destroy(entry.getKey());
    }
  }
Test queries with index on partitioned regions and concurrent PUT, DESTORY, INVALIDATE
operations. Make sure there is no UNDEFINED in the query result.
geode-core/src/integrationTest/java/org/apache/geode/cache/query/functional/IndexOnEntrySetJUnitTest.java