@Override
    public Authentication readAuthentication(final ServerCall<?, ?> call, final Metadata headers) {
        log.debug("Continue with anonymous auth");
        return new AnonymousAuthenticationToken(this.key, this.principal, this.authorities);
    }
Creates a new AnonymousAuthenticationReader with the given key,principal and authorities.

@param key The key to used to identify tokens that were created by this instance.
@param principal The principal which will be used to represent anonymous users.
@param authorities The authority list for anonymous users.
grpc-server-spring-boot-starter/src/main/java/net/devh/boot/grpc/server/security/authentication/AnonymousAuthenticationReader.java