Thinking of writing an email library for Rust

I have a long history (27 years) of writing email software - who knows, maybe someone here even recognizes my name(?), but I'm pretty new to Rust.

I've written multiple desktop email clients, multiple widely used email libraries, and now I am working on an email server professionally.

I know there are crates like `mime-parser` and `mailparse` and `lettre` but I think I can do better.

I was actually just reading the announcement post for `mime-parser` from 5 years ago and it seems people were very against `unsafe` code, so the question I have is:

If I *were* to implement this library for Rust, should I or should I not optimize it using SIMD? It seems SIMD would mean unsafe code if I am not mistaken.

If most of the Rust community would avoid my library because it was used `unsafe` code, then I want to know that before I make the time investment. To be fair, I've already implemented an incremental base64 encoder, base64 decoder, uuencoder, and a uudecoder using SIMD in Rust and they are blazing fast and all have scaler fallbacks which are also as fast as humanly possible, but I've got plenty more tricks up my sleeve for the actual *parsing* of MIME messages.

Is there a standard way people have addressed this in other creates? E.g. shipping an accelerated vs non-accelerated version of the same crate somehow?