private void forceQueueFlush() {
    FORCE_ASYNC_QUEUE = false;
    final DMStats stats = getSystem().getDistributionManager().getStats();
    WaitCriterion ev = new WaitCriterion() {
      @Override
      public boolean done() {
        return stats.getAsyncThreads() == 0;
      }

      @Override
      public String description() {
        return "Waiting for async threads to disappear";
      }
    };
    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