Feature Request: Implement NSURLSession for file Uploads/Downloads (iOS7+)

[GoogleCodeExporter]

What steps will reproduce the problem?
- uploads/downloads can be cancelled when the App is terminated 
- uploads/downloads can be cancelled when entering the lock screen in certain 
situations (ex: going to the lock screen while the app is in the foreground)
- uploads/downloads can be delayed until a background fetch occurs (especially 
problematic for large files that take over 10 minutes to download)

What is the expected output? What do you see instead?
- Using NSURLSession would ensure downloads occur regardless of the App's state 
(in the foreground, background, or terminated).

What version of the product are you using? On what operating system?
- Google-API-Client/Drive 0.1 via CocoaPods
- iOS 8.1

Please provide any additional information below.
I'm unsure if this should be placed here or in the GTM: HTTP Fetcher project

Original issue reported on code.google.com by dnd.c...@gmail.com on 18 Nov 2014 at 5:22

[GoogleCodeExporter]

There is already an NSURLSession-based fetcher, and the API library can be 
built to use it by setting the GTM_USE_SESSION_FETCHER flag.

https://code.google.com/p/gtm-session-fetcher/

Unfortunately, we've not had time to document the new fetcher, and we're still 
actively developing (and debugging) it.

Original comment by grobb...@google.com on 4 Dec 2014 at 10:00

• Changed state: Done