private void forceQueuing(final Region r) throws CacheException {
    FORCE_ASYNC_QUEUE = true;
    final DMStats stats = getSystem().getDistributionManager().getStats();
    r.put("forcekey", "forcevalue");

    // wait for the flusher to get its first flush in progress
    WaitCriterion ev = new WaitCriterion() {
      @Override
      public boolean done() {
        return stats.getAsyncQueueFlushesInProgress() != 0;
      }

      @Override
      public String description() {
        return "waiting for flushes to start";
      }
    };
    GeodeAwaitility.await().untilAsserted(ev);
  }
Test to make sure slow receiver queuing is working

@since GemFire 4.2.1
geode-core/src/distributedTest/java/org/apache/geode/cache30/SlowRecDUnitTest.java