https://crates.io/crates/milter
This is a new crate under development, containing Rust bindings to libmilter, the sendmail mail filter API. Milters are programs that can be integrated with mail servers like Postfix.
This is likely of extremely marginal interest to most of you … but who knows – if you are interested in ancient mail server technology, please check it out! I’m happy to receive feedback of any kind, here or on the issue tracker.