public static Ip4Prefix valueOf(int address, int prefixLength) {
        return new Ip4Prefix(Ip4Address.valueOf(address), prefixLength);
    }
@Test
    public void testToStringIPv4() {
        Ip4Prefix ipPrefix;

        ipPrefix = Ip4Prefix.valueOf("1.2.3.0/24");
        assertThat(ipPrefix.toString(), is("1.2.3.0/24"));

        ipPrefix = Ip4Prefix.valueOf("1.2.3.4/24");
        assertThat(ipPrefix.toString(), is("1.2.3.0/24"));

        ipPrefix = Ip4Prefix.valueOf("0.0.0.0/0");
        assertThat(ipPrefix.toString(), is("0.0.0.0/0"));

        ipPrefix = Ip4Prefix.valueOf("255.255.255.255/32");
        assertThat(ipPrefix.toString(), is("255.255.255.255/32"));
    }