@Override
      public Object call() {
        Region<CustId, Customer> pr = getCache().getRegion(CUSTOMER);
        assertNull(pr.get(key));
        getCache().getCacheTransactionManager().begin();
        pr.putIfAbsent(key, new Customer("name1", "address"));
        assertNotNull(pr.get(key));
        return null;
      }
test has a client, two accessors and a datastore pool connects to two accessors. we then close
the server in first accessor and verify failover
geode-core/src/distributedTest/java/org/apache/geode/internal/cache/ClientServerTransactionDUnitTest.java