Add async support

[taschmidt]

These bulk of these changes are to add async support to the batch extensions in the form of DeleteAsync and UpdateAsync methods.

It also adds async support to the caching extensions with the methods FromCacheAsync and FromCacheFirstOrDefaultAsync.

[pwelter34]

Why IList instead of IEnumerable? Would like some reason before making that change. Thanks!

[taschmidt]

Because of the add lambda on line 39, the underlying object will always be an IList<T> so why not return the most functional interface you can? In this case, the user can then make use of Count and random access using Item.

[ghost1face]

I am using this library as well and found there was no async support for Cache and started writing my own for a pull request, then stumbled upon this one. @pwelter34 is there any plan on merging this in the code-base? @taschmidt I feel that's a rare case (although still valid) but I typically believe in implementing the IEnumerable instead of IList. Good work though, you beat me to it! 👍

[taschmidt]

Yeah, as far as the IList goes, it was something that helped me out and I figured it couldn't hurt. But yes, I could've easily worked around it. I actually didn't mean for it to piggy-back onto my async change since the two don't have much to with each other.

But yeah, @pwelter34, what's the status here?

[taschmidt]

Awesome! Any idea when you'll push a new nuget package? I would love to get rid of my pinned assembly! :)

[michaelvolz]

Any plans to release a new nuget package with these updates?