public static String toStringAddress(SocketAddress address) {
        if (address == null) {
            return StringUtils.EMPTY;
        }
        return toStringAddress((InetSocketAddress) address);
    }
@Test
    public void testToStringAddress2() {
        assertThat(NetUtil.toStringAddress(ipv4)).isEqualTo(
            ipv4.getAddress().getHostAddress() + ":" + ipv4.getPort());
        assertThat(NetUtil.toStringAddress(ipv6)).isEqualTo(
            ipv6.getAddress().getHostAddress() + ":" + ipv6.getPort());
    }