我正在尝试使用NSURLSession在后台下载100个文件。 （修改了Apple的示例代码 - SimpleBackgroundTransfer）。在iPhone中我得到以下日志
nsnetworkd[298] <Error>: Canceling SSDownload: <SSDownload: 0x15ee62760>: -9205186979102545636 (task (null)) since it's not associated with a task or the phase is not SSDownloadPhaseDownloading
mstreamd[335] <Notice>: (Note ) mstreamd: Not monitoring for external power.
mstreamd[335] <Notice>: (Note ) PS: Media stream daemon stopping.
mstreamd[335] <Notice>: (Note ) AS: <MSIOSAlbumSharingDaemon: 0x15ee18bb0>: Shared Streams daemon has shut down.
mstreamd[335] <Notice>: (Warn ) mstreamd: mstreamd shutting down.
mstreamd[336] <Notice>: (Note ) mstreamd: mstreamd starting up.
mstreamd[336] <Notice>: (Note ) PS: Media stream daemon starting...
有时iPhone因内存不足警告而崩溃
springBoard，backboardd，nsnetworkd每次都显示为最大进程。有人遇到过这个问题吗？任何帮助表示赞赏。