Adding JWT token Authentication information only possible after body processing

[envimate-opensource]

Do you have an awesome idea to improve the project? Please describe.
Adding authentication information into the body map should be possible BEFORE body
processing, so that the authorizer can reject a request even BEFORE the body is parsed.

Is your feature request related to a problem? Please describe.
That reduces the attack surface and hence increases security.

Describe the solution you'd like
I'd like to be able to call:

.configured(toAuthenticateRequests().beforeBodyProcessing().using(metaData -> {
                    final Optional<CustomerIdentifier> optionalId = metaData.get(HEADERS)
                            .getHeader("Authorization")
                            .map(authenticator::authenticateAs);
                    optionalId.ifPresent(customerIdentifier ->
                            metaData.get(BODY_MAP).put("customerIdentifier", customerIdentifier)
                    );
                    return optionalId;
                }))

without receiving a java.lang.RuntimeException: Could not find meta datum BODY_MAP ...

Additional context
none given