Rustls still outsources cryptographic primitives. I believe the currently supported providers of those are… drumroll… AWS-LC and Ring. The latter is a fork of BoringSSL. The article describes AWS-LC and BoringSSL as "Googled and Amazoned to death; they don't care about anyone but their own use cases".

The state of things sucks :-(

A c wrapper to rust feels like we've gone full circle

rustls doesn't have its own implementation of cryptography, you have to choose a provider like openssl or aws lc