多线程异步中PUT请求异常

[yu910520]

dispatch_group_t group = dispatch_group_create();
dispatch_group_async(group, GlobalQueue, ^{
dispatch_group_enter(group);
这里做YTK请求，进入请求流程后，失败或者成功的结果都没有返回。
dispatch_group_leave(group);
}
});