Add Support For ValueTask<>

[cportwood]

Currently value tasks are not supported. I know we can convert any ValueTask<> to a task but it would be nice to have the option to return a ValueTask<>.
Adding support would not be hard. It would just would just be adding a copy of Async versions for each Extension.
Thoughts?

[cportwood]

I would be willing to contribute if needed.

[cportwood]

Sorry, I did find that this was already suggested.

[vkhorikov]

Sorry for late reply, was on vacation. Yes, there already should be a ticket for this, feel free to submit a PR.