Doesn't rust have a standard solution for that?

If I use 10 libraries and they all use a different logging framework then that's ... not convenient.

It does, everyone uses the `log` crate. But then it wouldn't be zero-dependencies anymore.

In fairness it's already not really “zero dependency” since it uses rayon (for easy multithreading) and wide (for easy SIMD), using log would make total sense I think (not the main author, just a contributor).