5.0.2 LCN模式，补偿机制问题

```
public class LcnTransactionCleanService implements TransactionCleanService {

private final TCGlobalContext globalContext;

@Autowired
public LcnTransactionCleanService(TCGlobalContext globalContext) {
this.globalContext = globalContext;
}

@Override
public void clear(String groupId, int state, String unitId, String unitType) throws TransactionClearException {
try {
LcnConnectionProxy connectionProxy = globalContext.getLcnConnection(groupId);
connectionProxy.notify(state);
// todo notify exception
} catch (TCGlobalContextException e) {
log.warn("Non lcn connection when clear transaction.");
}
}
}
```
源码中，connectionProxy.notify(state) 里面实际上捕获了所有异常；
如果参与方等待通知时，数据库connection提交失败，那么是不是不会被记录需要补偿？

Start with LcnTransactionCleanService.clear and trace LcnConnectionProxy.notify(state) through TCGlobalContext. Investigate how exceptions from a participant's database commit are handled and whether failed notifications are recorded for compensation; done means the failure behavior is defined and covered by an appropriate test.

Scritto dal modello di indicizzazione a partire dal testo della issue.