Rust code automatically generated with the wayland-scanner crate for the input-method-unstable-v2 protocol from wlroots. Some parts might not be safe, even though they are not marked ad "unsafe". It is advised to use the wayland-protocols crate, once this protocol is included.
Have a look at the code of the zwp-input-method-service crate to see how you can use this protocol. Or you can use the zwp-input-method-service crate instead of this one to make it easier for you.
PR are always welcome :)