curl is dealing with the complexity of HTTP. Even doing a simple basic request to some website, is going to cover a lot of code paths to deal with all sorts of

curl is dealing with the complexity of HTTP. Even doing a simple basic request to some website, is going to cover a lot of code paths to deal with all sorts of response codes (redirects, etc.), headers, etc. It's likely that new Rust code would introduce more bugs, while curl is extremely well tested at this point.