Crazy thought: what if I added another request handler language to #iocaine? What if it was #Rust?
Not quite sure how it would work, but the request handler would be a crate-type = ["cdylib"]
thing. That might be even more performant than Roto, and would allow doing a whole lot of things neither the Roto nor the Lua/Fennel engines can (because they're intentionally locked down, while due to the nature of being a cdylib, Rust wouldn't be).