private static void registerKey(Object key) {
    try {
      registerKeyOnly(key);
    } catch (Exception ex) {
      Assert.fail("failed while registering key(" + key + ")", ex);
    }
  }
wait for queues to drain in the server
geode-core/src/distributedTest/java/org/apache/geode/internal/cache/tier/sockets/InterestListDUnitTest.java