Lix support

[nrabulinski]

Hey, I maintain https://git.lix.systems/nrabulinski/attic which (very loosely) follows both attic's and lix's main for my own personal use. Previously it wasn't feasible for me to offer any more maintenance than that which is why that fork only supports Lix, and only the commit my own configuration is at. Nowadays it's a bit different so my question is whether upstream support for Lix would be welcome? My plan would be to follow stable Lix releases and (roughly) main for those living on the edge. If you don't want that, that's fine but if you think you could accept that - I'll prepare a PR :)

[nrabulinski]

@zhaofengli I've seen you porting my changes, thanks! As a heads up, between Lix 2.92 (current stable) and 2.93 (unreleased yet) Lix moved to using kj-async for pretty much all store-related tasks inside the codebase. This means it no longer plays nicely with Rust's async as the ffi cannot be created on one thread and destroyed on another as that'll result in an exception.
What I did is I created a dedicated thread solely for ffi and the rest of the app talks to it over channels. It's not the most elegant and I don't think it's production ready as it stands, but I wanted something that works for my needs for now. I'm pretty sure this implementation should be backwards compatible so you may want to start thinking about similar solution, if you want to be compatible in the future.
Ref: https://git.lix.systems/nrabulinski/attic/commit/100eae5b9d2e182fb654ed31392d26747f0bcfbb