[egorfine]

Why not spend the efforts to speed up the real zlib? So that the whole world actually gets to spin a bit faster.

Rust folks are claiming excellent interoperability with C binaries. Why the need for a rewrite then?

[swiftcoder]

Maybe because the speed up is easier to attain in a language where you aren't constantly worrying about introducing bugs? Maybe development is easier in a language with more modern tooling?

Interoperability runs both ways, everyone currently taking a dependency on the C library can swap in the rust library in its place and see the same benefits