private void throwTransactionCallbackException() throws Exception {
        TestTxListener l = (TestTxListener) getCache().getTxManager().getListener();
        if (l.ex != null) {
          throw l.ex;
        }
        TestTxWriter w = (TestTxWriter) getCache().getTxManager().getWriter();
        if (w.ex != null) {
          throw w.ex;
        }
      }
When we have narrowed down on a target node for a transaction, test that we throw an exception
if that node does not host primary for subsequent entries
geode-core/src/distributedTest/java/org/apache/geode/internal/cache/RemoteTransactionDUnitTest.java