public int size() {
        return endpoints.size();
    }
@Test
    void testSize() {
        Map<ListenerName, InetSocketAddress> endpointMap = Utils.mkMap(
                Utils.mkEntry(testListener, testSocketAddress));

        assertEquals(1, Endpoints.fromInetSocketAddresses(endpointMap).size());
        assertEquals(0, Endpoints.empty().size());
    }