public static LinkDescription combine(BasicLinkConfig cfg, LinkDescription descr) {
        if (cfg == null) {
            return descr;
        }

        Link.Type type = descr.type();
        if (cfg.isTypeConfigured()) {
            if (cfg.type() != type) {
                type = cfg.type();
            }
        }

        SparseAnnotations sa = combine(cfg, descr.annotations());
        return new DefaultLinkDescription(descr.src(), descr.dst(), type, sa);
    }
@Test
    public void testDescOps() {
        LinkDescription desc = BasicLinkOperator.combine(BLC, LD);
        assertEquals(String.valueOf(NTIME), desc.annotations().value(AnnotationKeys.LATENCY));
        assertEquals("true", desc.annotations().value(AnnotationKeys.DURABLE));
    }