It's not a solved problem in rust or go. It's still easier to write understandable text processing code in Python, Perl, Ruby, lisp than in Go or Rust.

Also for web backend Go, Rust cannot close the gap with Python or Ruby or lisp easily. Rust and Go are strong in their own domain writing web backend is not one of them. It does not mean one cannot write, it's just a lot of work.

When dealing with MIME types or REST or HTML or XML etc. dynamic typed languages are still easy, readable with reasonable performance. Only when one wants high performance, will go through the path of writing API in go or rust.