private void performUpdate(VM memberVM) {
    memberVM.invoke("perform update", () -> {
      DMStats stats = ((InternalDistributedSystem) cache.getDistributedSystem())
          .getDistributionManager().getStats();
      long reconnectAttempts = stats.getReconnectAttempts();
      cache.getRegion(regionName).put("testKey", "updatedTestValue");
      assertThat(stats.getReconnectAttempts()).isEqualTo(reconnectAttempts);
    });
  }
This class tests cluster tcp/ip communications both with and without SSL enabled
geode-core/src/upgradeTest/java/org/apache/geode/ClusterCommunicationsDUnitTest.java