Searching around, I found someone that benchmarked gobgp, rustybgp, and some others, and gobgp didn't seem to do all that well compared to other implementations.
https://elegantnetwork.github.io/posts/comparing-open-source...
https://elegantnetwork.github.io/posts/comparing-open-source...
Also, they have a Rust version: https://github.com/osrg/rustybgp