@Override
    public String toString() {
        return MoreObjects.toStringHelper(getClass())
            .add("prefix", prefix)
            .add("nextHop", nextHop)
            .toString();
    }
@Test
    public void testToString() {
        Ip4Prefix prefix = Ip4Prefix.valueOf("1.2.3.0/24");
        Ip4Address nextHop = Ip4Address.valueOf("5.6.7.8");
        RouteEntry routeEntry = new RouteEntry(prefix, nextHop);

        assertThat(routeEntry.toString(),
                   is("RouteEntry{prefix=1.2.3.0/24, nextHop=5.6.7.8}"));

        Ip6Prefix prefix6 = Ip6Prefix.valueOf("1000::/64");
        Ip6Address nextHop6 = Ip6Address.valueOf("2000::1");
        RouteEntry routeEntry6 = new RouteEntry(prefix6, nextHop6);

        assertThat(routeEntry6.toString(),
                   is("RouteEntry{prefix=1000::/64, nextHop=2000::1}"));
    }