private void setQRMslow() throws InterruptedException {
    int oldMessageSyncInterval = cache.getMessageSyncInterval();
    cache.setMessageSyncInterval(6);
    Thread.sleep((oldMessageSyncInterval + 1) * 1000);
  }
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