Support HttpRequest as a method parameter in JWTClaimsValidator

[arunapi]

In order to reduce the (bot)attack surface of my endpoint, I want to tie down a JWT token to the user agent (HTTP request header) and session (an HTTP Cookie).
I want to validate if the HTTP request made with a JWT token (Authorization header) has the user_agent and session claims and it matches the user-agent header and session cookie in the HTTP request.

As per the documentation, I have an easy way to create JWT token claims from HttpRequest headers or Cookie values
https://micronaut-projects.github.io/micronaut-security/latest/guide/#claimsGeneration

It would be nice, if the JwtClaimsValidator also supports HttpRequest object as a parameter, in order to perform claims validation.

The solution recommended to work around the limitation is to use

Optional<HttpRequest<Object>> httpRequestOptional = ServerRequestContext.currentRequest();

Since the above line of code is not very common in other places of the project, please advise if using the above code has any performance implications.

Example Application

I've created a sample application with the above feature and the recommended solution.
https://github.com/arunapi/micronaut-jwt-sec-app

I am reporting this issue as per the request from @jameskleeh in order to describe my use case.
https://gitter.im/micronautfw/questions?at=5f621df2a9c2c8511e9bb040