[Cocos2d-x v3.10] [ios]Crash when using CCDownloader

My device is iphone 4, ios 7.1.2.
What I did is:

  1. create a new CCDownloader
  2. download a file
  3. crashed

auto d = new network::Downloader({ 1, 5 ,".tmp" });
d->onDataTaskSuccess = [d](const network::DownloadTask& task, std::vector& data){
log(“done 1”);
};
d->createDownloadDataTask(“http://128.199.131.108/mantis.zip”, “1”);

Does anyone have the same problem?