Even if performance matter Go should be a better choice.
Go's performance is very close to rust in Web ecosystem and is very mature.
I haven't noticed that C# is faster than Go, or that it's as fast as Rust/C++. Except in selected micro-benchmarks, of course.
C# is at best in the same bracket as Go: https://www.techempower.com/benchmarks/#section=data-r19&hw=...
Compared to the golang version using fasthttp, which is non-standard and makes compromises to achieve speed, and I'd avoid it for production.