docs: public User resolveUser(final String username) throws SQLException {
        metrics.usernameCacheTries.mark();
        User user = usernameCache.getIfPresent(username);
        if(user != null) {
           metrics.usernameCacheHits.mark();
           return user;
        } else {
           user = selectUser(username);
           if(user != null) {
              usernameCache.put(username, user);
           }
           return user;
        }
     }