private static void addCacheLoader() {
    // Add a cache loader
    Region region = cache.getRegion(REGION_NAME);
    region.getAttributesMutator().setCacheLoader(new ReturnKeyCacheLoader());
  }
wait for queues to drain in the server
geode-core/src/distributedTest/java/org/apache/geode/internal/cache/tier/sockets/InterestListDUnitTest.java