@Override
    public String begin(String applicationId, String transactionServiceGroup, String name, int timeout)
        throws TransactionException {
        GlobalSession session = GlobalSession.createGlobalSession(applicationId, transactionServiceGroup, name, timeout);
        MDC.put(RootContext.MDC_KEY_XID, session.getXid());

        session.begin();

        // transaction start event
        MetricsPublisher.postSessionDoingEvent(session, false);

        return session.getXid();
    }
@Test
    public void beginTest() throws Exception {
        String xid = core.begin(applicationId, txServiceGroup, txName, timeout);
        globalSession = SessionHolder.findGlobalSession(xid);
        Assertions.assertNotNull(globalSession);

    }