POC: Redesign without IO

[gatorcse]

I experimented with changing #155 to not require IO. The stated reasons for specifying IO were for Ref and Deferred, but those only require Sync and Concurrent respectively. I wanted to see if we could remove the requirement for IO, allowing Monix or other implementations to be used.

This is just a proof of concept. I didn't update the tests or anything, it also adds a F[_] parameter all over the place. This can probably be wrapped up in an abstract class or something to simplify the API. I just wanted to see if it would work.

[gatorcse]

This doesn't compile because the call to .empty requires the implicit Sync instance, which is in the implicit argument list that follows, but that is not important to the concept.

[gatorcse]

Doesn't need IO, just an implicit Sync

[gatorcse]

Doesn't need IO, just an implicit Concurrent

[purrgrammer]

Interesting, thanks for the PR. I'm going to update it to match what's in redesign right now and make it compile and I'll come back here to write my thoughts on this approach.

[raulraja]

@gatorcse great stuff 👏 . The clear advantage of being more generic is that we can run Fetch to monix Task and any other data type that already provides instances for cats-effect.

[purrgrammer]

I managed to make it compile, removing the F parameter from a couple places like DataSource (it is instead now passed to DataSource#fetch and DataSource#batch). I still need to update the examples/tests and the documentation, but I think I'm going to incorporate this into the redesign branch.

Awesome work @gatorcse, thanks for doing the heavy lifting with this changes.

[purrgrammer]

Added these improvements to #155 ✨