protected void createSenderInVm4() throws IOException {
    createSender("ln", 2, true, true, numDispatchers, DEFAULT_ORDER_POLICY);
  }
Since the sender is attached to a region and in use, it can not be destroyed. Hence, exception
is thrown by the sender API.
geode-wan/src/distributedTest/java/org/apache/geode/internal/cache/wan/serial/SerialGatewaySenderOperationsDistributedTest.java