class LocalConfigurationService implements LocalConfiguration, Serializable {

    @Override
    public Set<String> keys() {
        return rawDelegates
                .stream()
                .flatMap(d -> d.keys().stream())
                .flatMap(k -> !k.startsWith(plugin + '.') ? Stream.of(k)
                        : Stream.of(k, k.substring(plugin.length() + 1)))
                .collect(toSet());
    }

}