Multi subscribe

I put the subscribe in Onconnect.when connect success,it will subscribe the collecion.
```
String flag = null;

onConnect(){
if (flag !=null)return
flag = singleinstance.subscrbe("any collections")
}
onDisconnect(){
flag =null;
}
```
above is the code what i subscribe.

now the ques is:in local test env,i see no multi subscribe.
but in the online env,in the monitor,the logs show that the app always subscribe the method,
i am confuse,so i ask the ques in here,hope your reply!