Log raw request body before deserialization in Spring Boot REST controller

Given the following, kind of basic, REST controller in Spring Boot:

@RestController
public class NotificationController {

    @PostMapping(path = "/api/notification")
    public void handleNotification(@RequestBody @Valid NotificationRequest request) {
        System.out.println(request.getMessage());
    }
}

One requirement is to log the incoming request body before deserializing it to a NotificationRequest. We'd like to have a trace, e.g. if the request is not well-formed. My first idea was to use the HttpServletRequest directly but then I would lose the validation and automatic deserialization.

public void handleNotification(HttpServletRequest httpRequest) {
  // ...
}

Is there some mechanism to log the incoming "raw" request body for this particular endpoint?