A drop-in equivalent replacement for NSURLSession with better blocks support

Behaviour should be identical to NSURLSession as all actual work is forwarded to an NSURLSession instance internally. The only difference is that completion blocks and delegate callbacks are not mutually exclusive (which they are with NSURLSession).

The only NSURLSession method not supported is sharedSession which is a bad idea IMO anyway.

For the love of Cocoa, why?

I like NSURLSession. It makes easy things easy and hard things possible, which is good, but a great api should also not behave in unexpected ways. Unfortunately NSURLSession has a few unexpected behaviours. The first one that tripped me up is that as soon as you use the convenient completionHandler blocks, you no longer get delegate callbacks for those tasks. Why? I have no idea. It is documented, but I found it unexpected and akward. The completionHandler blocks are not direct replacements for the delegate methods and so are basically useless.

An obvious workaround could be implemented with a category, but another unexpected thing about NSURLSession is it's class hierarchy seems to be pretend (compare the docs with what isKindOfClass returns for an NSURLSessionDownloadTask in the real world...). NSURLSession also cannot be transparently subclassed because, amongst other issues, it's class methods do not return instancetype.

But I still like the NSURLSession api, it strikes the balance between being simple and powerful very elegantly.

So I decided to wrap NSURLSession in a near-transparent drop-in wrapper that calls both delegate methods and completionHandler blocks.

Y U no CocoPod?

This is too early to even reasonably be called version 0.0.1.

Caveats

This is a very early release. The only thing I'm using it for in any meaningful way is simple data tasks and download tasks, YMMV.

Please submit bug reports and pull requests.

TODO

I plan to also expand block support very simply, by adding further convenience methods with additional progress completion callback blocks, eliminating the need for a delegate in simple cases.