Persistent queues are really useful. I have envied Android developers for having the Tape queue http://square.github.io/tape/ and the Android Priority Jobqueue https://github.com/yigit/android-priority-jobqueue
Below I have compiled a list of the persistent queue implementations for iOS that I know of. Most of them are not in active development. Ping me if you want a library added to the list.
- https://github.com/linkedin/cassette
- https://github.com/lucas34/SwiftQueue
- https://github.com/teambition/Queue
- https://github.com/ryanbaldwin/Cute
- https://github.com/THREDOpenSource/SYNQueue
- https://github.com/thisandagain/queue (Oleg Shanyuk has picked up development of this on https://github.com/gelosi/queue and Wolfpack-Digital on https://github.com/Wolfpack-Digital/queue)
- https://github.com/segmentio/cassette (LinkedIn is maintaining a version of this. See further up)
- https://github.com/kevboh/KTBTaskQueue
- https://github.com/togethera/Kyu
- https://github.com/marcoarment/FCOfflineQueue
- https://github.com/inf0rmer/BAPersistentOperationQueue
- https://github.com/smalllixin/LxTaskQueue
- https://github.com/gcamp/IPOfflineQueue
LinkedIn is now actively maintaining an iOS variant of Tape here: https://github.com/linkedin/cassette