Support for validating message

[matino]

I'd like to return HTTP 400 in case the message text is longer than X characters.
Currently I don't have other option but write a middleware that parses the raw HTTP request. That's not optimal, since the parsing is already done on the server. Is there any other option?

[hyprh]

Does the middleware mentioned here refer to the middleware configured on our server? I think we can intercept requests via the Content-Length header, or we can validate the request body length in the ProcessMessage method—what do you think about this approach? If it doesn’t work for our scenario, we can continue discussing adjustments.

https://github.com/trpc-group/trpc-a2a-go/blob/main/examples/multi_endpoint/server/main.go