XMPPElementReceipt *receipt = [XMPPElementReceiptnew];

//    * - Do an instantaneous check (pass timeout == 0)

//    * - Wait until the element has been sent (pass timeout < 0)

//    * - Wait up to a certain amount of time (pass timeout > 0)

    [mStream sendElement:message andGetReceipt:&receipt];

    [receipt wait:-1];

 

//    * If you later want to check to see if the element has been sent:

//        *

//        * if ([receipt wait:0]) {

//            *   // Element has been sent

//            * }

//    *

//    * If you later want to wait until the element has been sent:

//    *

//    * if ([receipt wait:-1]) {

//        *   // Element was sent

//        * } else {

//            *   // Element failed to send due to disconnection

//            * }

    if ([receipt wait:-1])

    {

        TTLog(@"was sent");

    }

    else{

        TTLog(@"sent faild");

    }

 1,receipt wait = 0,即时检查，不过要 结合timer，不然的话，马上检查一定发送失败的，

2，receipt wait > 0,等上几分钟检查，如果是 放到主线程，会卡几分钟的，如果改成异步的是没有问题的，不过，即便是异步，设置等待的时间太短，即便发送成功了，也会返回no 的

 BOOL messageState =[receipt wait:0.0000001];

    if (messageState)

    {

        TTLog(@"was sent");

    }

    else{

        TTLog(@"sent faild");

    }

3，receipt wait < 0,等待发送完检查，同样的放到主线程，会卡的，同上，