public static <T extends ConfigInstance> JRTClientConfigRequest createFromSub(JRTConfigSubscription<T> sub) {
        // TODO: Get trace from caller
        return JRTClientConfigRequestV3.createFromSub(sub, Trace.createNew(), compressionType, getVespaVersion());
    }
@Test
    public void testCreateFromSub() {
        Class<FunctionTestConfig> clazz = FunctionTestConfig.class;
        final String configId = "foo";
        TimingValues timingValues = new TimingValues();
        JRTConfigSubscription<FunctionTestConfig> sub =
                new JRTConfigSubscription<>(new ConfigKey<>(clazz, configId),
                                            new JRTConfigRequester(new JRTConnectionPool(new ConfigSourceSet("tcp/localhost:12345")), timingValues),
                                            timingValues);

        JRTClientConfigRequest request = JRTConfigRequestFactory.createFromSub(sub);
        assertThat(request.getVespaVersion().get(), is(defaultVespaVersion));
    }