private void verifyEntrySize(String regionName, final int expectedMembers) {
    DistributedRegionMXBean distributedRegionMXBean =
        awaitDistributedRegionMXBean(regionName, expectedMembers);
    assertThat(distributedRegionMXBean).isNotNull();
    assertThat(distributedRegionMXBean.getEntrySize()).isGreaterThan(0);
  }
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