I am actually really excited about this. The issues I've had with function colouring had to do with trying to compose code using (or expecting) blocking effect

I am actually really excited about this. The issues I've had with function colouring had to do with trying to compose code using (or expecting) blocking effects with those using async effects in NodeJS - if one library has a higher-order function that expects a non-async function and you have functionality which is provided to you as async, it can be very difficult to plumb them together! And if it's the other way around, it can be quite the performance killer (think how much faster better-sqlite3 is than alternatives). Zig's approach eliminates this problem, AFAICT. If I had to choose between having to pass through an effect handler like `io` or write `async` everywere, the former seems like a better use of my time. It's explicit, but that can be good. It also fits Zig well with the allocator. Code can expect an allocator or perhaps an allocator and `io`, or perhaps neither. It's analogous to Rust code that is core vs alloc/nostd vs std. I am slightly amused that a "C-but-better" language is going to have an `io` passed through non-pure functions much like Haskell. It's that idea combined with Rust's pluggable async runtimes (and stackless concurrency) combined with Roc's "platforms" - but for systems programmers. Quite amazing.