pub fn generate_client(&self, service: &impl Service, proto_path: &str) -> TokenStream {
        crate::client::generate_internal(
            service,
            self.emit_package,
            proto_path,
            self.compile_well_known_types,
            self.build_transport,
            &self.attributes,
            &self.disable_comments,
        )
    }
Generate client code based on `Service`.

This takes some `Service` and will generate a `TokenStream` that contains
a public module with the generated client.
tonic-build/src/code_gen.rs