@Override
  public final void preTearDown() throws Exception {
    client1.invoke(RegisterInterestBeforeRegionCreationDUnitTest::closeCache);
    client2.invoke(RegisterInterestBeforeRegionCreationDUnitTest::closeCache);
    server1.invoke(RegisterInterestBeforeRegionCreationDUnitTest::closeCache);
    server2.invoke(RegisterInterestBeforeRegionCreationDUnitTest::closeCache);
  }
close the cache on all the vms
geode-core/src/distributedTest/java/org/apache/geode/internal/cache/tier/sockets/RegisterInterestBeforeRegionCreationDUnitTest.java