fn generate_deserializer(
        &self,
        _name: &str,
        _shape: &Shape,
        _service: &Service<'_>,
    ) -> Option<String> {
        None
    }
If necessary, generate a deserializer for the specified type
This should be necessary only if `deserialize_trait` returns `None`
service_crategen/src/commands/generate/codegen/mod.rs