[REQ] Separate request/response type conversion from server setup

Is your feature request related to a problem? Please describe.

I'm using generated code, in particular from the rust-server generator, to create an API to be implemented for a FaaS runtime (eg. Lambda). The requests are going to be routed to functions by an API Gateway, so I don't need web server setup, but I would benefit from the code to convert between API request/response types into HTTP requests/responses.

Describe the solution you'd like

Generate the server code such that methods for converting HTTP requests into API requests and API responses into HTTP responses are exposed to the consumer.
In particular, for Rust, it would make sense if std::convert::TryInto or std::convert::TryFrom were implemented.

Describe alternatives you've considered

Using the entire handler code from the generated server in each lambda. This seems overcomplicated.

Additional context

Start by locating the rust-server generator and its generated server handler. Trace how API Gateway requests become HTTP requests and how HTTP responses become API responses, then determine how those conversions can be exposed without requiring web-server setup. Done means generated Rust code provides reusable conversion methods for both directions while preserving the existing server behavior.