@Test
  public void testReplicatedSerialPropagationWithParallelThreads() throws Exception {

    Integer lnPort = vm0.invoke(() -> WANTestBase.createFirstLocatorWithDSId(1));
    Integer nyPort = vm1.invoke(() -> WANTestBase.createFirstRemoteLocator(2, lnPort));

    createCacheInVMs(nyPort, vm2, vm3);
    createReceiverInVMs(vm2, vm3);

    createCacheInVMs(lnPort, vm4, vm5, vm6, vm7);

    vm4.invoke(() -> WANTestBase.createConcurrentSender("ln", 2, false, 100, 10, false, false, null,
        true, 4, OrderPolicy.THREAD));
    vm5.invoke(() -> WANTestBase.createConcurrentSender("ln", 2, false, 100, 10, false, false, null,
        true, 4, OrderPolicy.THREAD));

    vm2.invoke(
        () -> WANTestBase.createReplicatedRegion(getUniqueName() + "_RR", null, isOffHeap()));
    vm3.invoke(
        () -> WANTestBase.createReplicatedRegion(getUniqueName() + "_RR", null, isOffHeap()));

    startSenderInVMs("ln", vm4, vm5);

    vm4.invoke(
        () -> WANTestBase.createReplicatedRegion(getUniqueName() + "_RR", "ln", isOffHeap()));
    vm5.invoke(
        () -> WANTestBase.createReplicatedRegion(getUniqueName() + "_RR", "ln", isOffHeap()));
    vm6.invoke(
        () -> WANTestBase.createReplicatedRegion(getUniqueName() + "_RR", "ln", isOffHeap()));
    vm7.invoke(
        () -> WANTestBase.createReplicatedRegion(getUniqueName() + "_RR", "ln", isOffHeap()));

    vm4.invoke(() -> WANTestBase.doMultiThreadedPuts(getUniqueName() + "_RR", 1000));

    vm2.invoke(() -> WANTestBase.validateRegionSize(getUniqueName() + "_RR", 1000));
    vm3.invoke(() -> WANTestBase.validateRegionSize(getUniqueName() + "_RR", 1000));
  }
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