How "large" is the garbage collector penalty? My understanding is that the Go GC is significantly more efficient than for example JS's mark/sweep approach. Apples to oranges for sure, but I am interested in better understanding how expensive the Go GC is vs Rust performance.
The question here is how much can you disambiguate between the impact of GC and the impact of differently written code plus differently optimizing compiler backend (where Go is still very simple but Rust uses LLVM). If for example the Go code used goroutines and channels in those places where the rewritten Rust code uses asynchronous operations, that alone may account for substantial differences in performance.