(a) That's mostly irrelevant to my point. This project has major issues with an LLM signature in a safety-critical context. If we assume that the bun rust rewrite went off without a hitch and that doing so is repeatable then it's worth trying to understand what the difference was.

(b) I'm not sure those assumptions hold. Bug reports spiked 2-3x when the rust version was introduced. HMR broke. There were utf-16 parsing panics. The result was slower out of the box and needed a lot of hand-tuning. There were FFI regressions. The rust rewrite had its own concurrency bugs despite rust's "fearless concurrency." In a JS runtime where the rest of the ecosystem is already usually broken, especially since the bugs seemingly weren't safety-related, maybe that's fine, but it wasn't exactly a "no major issues" rewrite.