Do we need to support invoking sync functions?

[goodboy]

@jtrakk made a good point in gitter that supporting both async and regular functions for remote invocation is a bit odd and probably unnecessary. I think I agree; there ain't nothing a regular func can do that an async one can't. Unless I'm forgetting something I think it should be fine to just remove support for regular functions?

Off hand it would allow removing the slew of checks in _actor._invoke().

[ryanhiebert]

I'd be in favor of only supporting async functions, for exactly the reasons you describe. I don't think there's anything significant to be gained, but there is additional complexity that could easily be avoided.

[goodboy]

See the comment in richardsheridan/trio-parallel#2 which I think is more fuel for this change.

[goodboy]

Yah, I'm thinking for a .alpha0 release we just drop remote sync function calling support and defer to @richardsheridan's project.

[goodboy]

Yeah so TLDR: is that if we're calling sync funcs in some remote actor you'll need the tractor runtime anyway which means you should have the ability to wrap the call in an async func - so there should be no benefit to supporting that wrapping inside _actor._invoke.

I also think we should make a alt-projects list in the readme and point to others for this kind of thing.

[goodboy]

We already have a pointer to trio-parallel in the readme, so just need a PR removing the support now.