Spring Security Provide mechanism to map UserDetails to GrantedAuthority

If spring-security support such extension:

@FunctionalInterface
public interface UserAuthorityMapper {

    Collection<? extends GrantedAuthority> mapAuthorities(UserDetails user);

}

@FunctionalInterface
public interface UserRoleMapper extends UserAuthorityMapper {

    Collection<String> mapRoles(UserDetails user);

    @Override
    default Collection<? extends GrantedAuthority> mapAuthorities(UserDetails user) {
        return mapRoles(user).stream().map(SimpleGrantedAuthority::new).collect(Collectors.toList());
    }

}

and have a built-in implementation:

@Component
public class UsernameAndTypeRoleMapper implements UserRoleMapper {

    @Override
    public Collection<String> mapRoles(UserDetails user) {
        return List.of(mapUsername(user), mapUserType(user));
    }

    protected String mapUsername(UserDetails user) {
        return "USERNAME(" + user.getUsername() + ")";
    }

    protected String mapUserType(UserDetails user) {
        Class<?> c = ReflectionUtils.getEntityClass(user);
        String name = c.getSimpleName();
        if (!StringUtils.hasLength(name)) {
            name = c.getSuperclass().getSimpleName();
        }
        return name.toUpperCase();
    }

}

Then every user will have an unique username role and type role, take User admin = new User("admin") for example, role USERNAME(admin) and USER will be added to its authorities.

I would like to submit a PR if the team decide to accept this feature request.