private void awaitMemberCount(final int expectedCount) {
    DistributedSystemMXBean distributedSystemMXBean = awaitDistributedSystemMXBean();
    await()
        .untilAsserted(
            () -> assertThat(distributedSystemMXBean.getMemberCount()).isEqualTo(expectedCount));
  }
Add a Notification listener to DistributedSystemMBean which should gather all the notifications
which are propagated through all individual MemberMBeans Hence Region created/destroyed should
be visible to this listener
geode-core/src/distributedTest/java/org/apache/geode/management/RegionManagementDUnitTest.java