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

    createCacheInVMs(nyPort, vm2, vm3);
    vm2.invoke(() -> WANTestBase.createPartitionedRegion(getTestMethodName() + "_PR", null, 1, 100,
        isOffHeap()));
    vm3.invoke(() -> WANTestBase.createPartitionedRegion(getTestMethodName() + "_PR", null, 1, 100,
        isOffHeap()));
    createReceiverInVMs(vm2, vm3);

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

    vm4.invoke(() -> WANTestBase.createConcurrentSender("ln", 2, true, 100, 10, false, false, null,
        true, 3, OrderPolicy.KEY));
    vm5.invoke(() -> WANTestBase.createConcurrentSender("ln", 2, true, 100, 10, false, false, null,
        true, 3, OrderPolicy.KEY));
    vm6.invoke(() -> WANTestBase.createConcurrentSender("ln", 2, true, 100, 10, false, false, null,
        true, 3, OrderPolicy.KEY));
    vm7.invoke(() -> WANTestBase.createConcurrentSender("ln", 2, true, 100, 10, false, false, null,
        true, 3, OrderPolicy.KEY));

    vm4.invoke(() -> WANTestBase.createPartitionedRegion(getTestMethodName() + "_PR", "ln", 1, 100,
        isOffHeap()));
    vm5.invoke(() -> WANTestBase.createPartitionedRegion(getTestMethodName() + "_PR", "ln", 1, 100,
        isOffHeap()));
    vm6.invoke(() -> WANTestBase.createPartitionedRegion(getTestMethodName() + "_PR", "ln", 1, 100,
        isOffHeap()));
    vm7.invoke(() -> WANTestBase.createPartitionedRegion(getTestMethodName() + "_PR", "ln", 1, 100,
        isOffHeap()));

    startSenderInVMs("ln", vm4, vm5, vm6, vm7);

    // make sure all the senders are running before doing any puts
    vm4.invoke(() -> WANTestBase.waitForSenderRunningState("ln"));
    vm5.invoke(() -> WANTestBase.waitForSenderRunningState("ln"));
    vm6.invoke(() -> WANTestBase.waitForSenderRunningState("ln"));
    vm7.invoke(() -> WANTestBase.waitForSenderRunningState("ln"));

    // FIRST RUN: now, the senders are started. So, do some of the puts
    vm4.invoke(() -> WANTestBase.doPuts(getTestMethodName() + "_PR", 100));

    // now, stop all of the senders
    vm4.invoke(() -> WANTestBase.stopSender("ln"));
    vm5.invoke(() -> WANTestBase.stopSender("ln"));
    vm6.invoke(() -> WANTestBase.stopSender("ln"));
    vm7.invoke(() -> WANTestBase.stopSender("ln"));

    // SECOND RUN: keep one thread doing puts
    vm4.invokeAsync(() -> WANTestBase.doPuts(getTestMethodName() + "_PR", 1000));

    // verify region size remains on remote vm and is restricted below a specified limit (number of
    // puts in the first run)
    vm2.invoke(() -> WANTestBase.validateRegionSizeRemainsSame(getTestMethodName() + "_PR", 100));
  }
Normal scenario in which a sender is stopped.
geode-wan/src/distributedTest/java/org/apache/geode/internal/cache/wan/concurrent/ConcurrentParallelGatewaySenderOperation_1_DUnitTest.java