pub fn proto_path(mut self, proto_path: impl AsRef<str>) -> Self {
        self.proto_path = proto_path.as_ref().to_string();
        self
    }
Set the path to where tonic will search for the Request/Response proto structs
live relative to the module where you call `include_proto!`.

This defaults to `super` since tonic will generate code in a module.
tonic-build/src/prost.rs