The Rust base64 crate got a new release the other day, which removed (or rather deprecated for now) the simple encoding/decoding API and requires quite a bit boilerplate for such a simple task.
The maintainer does not see the point in providing a simpler API for the common cases because if the API is too difficult to use then Rust is just the wrong language for you 🙄
Too bad the crate has such a prominent name on crates.io and is used so widely. I hope that doesn't turn away too many beginners because something as simple as base64 handling is so complicated.
The data-encoding crate looks like a good alternative for the same tasks. It provides the same amount of flexibility while still providing a simple API for the common tasks.
data-encoding — Rust data encoding library
Efficient and customizable data-encoding functions like base64, base32, and hex | Rust/Cargo packagelib.rs