Is there a code-first approach in Rust to generate protobuf definitions?

Hello,
I would like to know if there is a crate in Rust that allows generating the ".proto" definition from Rust code (code-first approach) [similar to how it's done with OpenAPI]?

(For example, in C# there is protobuf-net which allows it)

Thank you in advance.

Rust Struct -> .Proto
Rust Struct -> Serde (Json) -> .Proto