@Test
  public void testNormalRegionSerialPropagation() throws Exception {
    Integer lnPort = vm0.invoke(() -> WANTestBase.createFirstLocatorWithDSId(1));
    Integer nyPort = vm1.invoke(() -> WANTestBase.createFirstRemoteLocator(2, lnPort));

    vm2.invoke(() -> WANTestBase.createCache(nyPort));
    vm2.invoke(
        () -> WANTestBase.createReplicatedRegion(getUniqueName() + "_RR", null, isOffHeap()));
    vm2.invoke(WANTestBase::createReceiver);

    WANTestBase.createCacheInVMs(lnPort, vm4, vm5);

    vm4.invoke(() -> WANTestBase.createConcurrentSender("ln", 2, false, 100, 10, false, false, null,
        true, 5, OrderPolicy.THREAD));
    vm5.invoke(() -> WANTestBase.createConcurrentSender("ln", 2, false, 100, 10, false, false, null,
        true, 5, OrderPolicy.THREAD));


    startSenderInVMs("ln", vm4, vm5);

    vm4.invoke(() -> WANTestBase.createNormalRegion(getUniqueName() + "_RR", "ln"));
    vm5.invoke(() -> WANTestBase.createNormalRegion(getUniqueName() + "_RR", "ln"));

    vm5.invoke(() -> WANTestBase.doPuts(getUniqueName() + "_RR", 1000));

    vm4.invoke(() -> WANTestBase.checkQueueStats("ln", 0, 0, 0, 0));

    vm5.invoke(() -> WANTestBase.checkQueueStats("ln", 0, 1000, 0, 0));

    vm5.invoke(() -> WANTestBase.validateRegionSize(getUniqueName() + "_RR", 1000));

    vm4.invoke(() -> WANTestBase.validateRegionSize(getUniqueName() + "_RR", 0));

    vm2.invoke(() -> WANTestBase.validateRegionSize(getUniqueName() + "_RR", 0));

    vm2.invoke(() -> WANTestBase.checkGatewayReceiverStats(0, 0, 0));

  }
All the test cases are similar to SerialWANPropagationDUnitTest except that the we create
concurrent serial GatewaySender with concurrency of 4
geode-wan/src/distributedTest/java/org/apache/geode/internal/cache/wan/concurrent/ConcurrentWANPropagation_2_DUnitTest.java