Fastify Rate Limit From Custom Auth Handler

Hi, I'm looking at using https://github.com/fastify/fastify-rate-limit and trying to fit it (or my project) to accommodate.

I want to:

1. check and apply the rate limit against IP address IF authorization token is bad/not-supplied etc.
2. check and apply the rate limit against user id IF authorization token is good

I decorate my fastify instance with something like:

```ts
fastify.decorate('authenticate', async function (request, reply) {
const token = request.headers.authorization?.replace('Bearer ', '');

if (!token) {

// ###
// WANT TO CHECK RATE LIMIT HERE AGAINST IP
// ###

return reply
.code(401)
.send(createFailResponseApiModel('68b59dd8d73f85a46a49a18d', 'No token provided'));
}

const verifyAccessTokenResult = verifyAccessToken(token);
if (!verifyAccessTokenResult.success) {

// ###
// WANT TO CHECK RATE LIMIT HERE AGAINST IP
// ###

return reply
.code(401)
.send(createFailResponseApiModel('68b59e0b91a929648f0fb03b', 'Invalid token'));
}

const sessionResult = getSessionFromUserClaims(
verifyAccessTokenResult.data,
);
if (!sessionResult.success) {

// ###
// WANT TO CHECK RATE LIMIT HERE AGAINST IP
// ###

return reply
.code(401)
.send(createFailResponseApiModel('68b59dfdb827d5a7354aaf33', 'Invalid session'));
}

request.session = sessionResult.data;

// ###
// WANT TO CHECK RATE LIMIT HERE AGAINST USER ID
// ###

return undefined;
});
```

If I use the plugin as written I have the option for setting a `hook` to `preHandler` or `onRequest`.

Both don't seem to apply well here, `onRequest` will trigger before my auth thus only `IP` is available. Whilst `preHandler` triggers after my auth and by that point its too late.

Maybe I'm missing something, be happy to hear of solutions?