This is a demonstration of how Rust's type system can be leveraged to make robust APIs with important compile-time checks. The documentation in this crate is written within the modules themselves, Start by looking into into "password_manager.rs" to begin.
This crate implements a password manager API. In most languages, you'd be forced to add an isUnlocked field to your PasswordManager class and call it a day. Maybe, if you wanted to be fancy, you'd return an Option<Password> to indicate whether the manager was unlocked or not. Or, you could have an UnlockedPasswordManager class and a LockedPasswordManager class where you'd have to manually ensure that any common fields or functionality were updated on both. Using generic types, Rust automatically creates an Unlocked and Locked variant of the PasswordManager struct at compile time, preserving common functionality while also allowing separate methods to be defined for them.