private void clientPut(VM vm, final Object key, final Object value) {
    // performing put from the client1
    vm.invoke(new CacheSerializableRunnable("putFromClient") {
      @Override
      public void run2() throws CacheException {
        Region region = cache.getRegion(SEPARATOR + REGION_NAME);
        assertNotNull(region);
        region.put(key, value);
      }
    });
  }
This is to test the serialization mechanism of ClientUpdateMessage. Added after CQ support.
This could be done in different way, by overflowing the HARegion queue.
geode-cq/src/distributedTest/java/org/apache/geode/internal/cache/ha/HADispatcherDistributedTest.java