private void stopSendersAsync() throws InterruptedException {
    AsyncInvocation inv1 = vm4.invokeAsync(() -> stopSender("ln"));
    AsyncInvocation inv2 = vm5.invokeAsync(() -> stopSender("ln"));
    AsyncInvocation inv3 = vm6.invokeAsync(() -> stopSender("ln"));
    AsyncInvocation inv4 = vm7.invokeAsync(() -> stopSender("ln"));
    inv1.await();
    inv2.await();
    inv3.await();
    inv4.await();
  }
Put entries in region after gateway sender is stopped. Count number of PQRM messages sent.
geode-wan/src/distributedTest/java/org/apache/geode/internal/cache/wan/parallel/ParallelGatewaySenderOperationsDistributedTest.java