Add const unsafe new_unchecked to Ipv4Network & Ipv6Network

[aurelilys]

Hello 😃

I've encountered a problem using your crate, when I want to define an &[Ipv4Network], I'm not able to get the result, unwrap() is not marked as const. One of the solutions I've found would be to introduce two new new_unchecked functions for Ipv4Network and Ipv6Network. This would make it possible to:

const TEST: &[Ipv4Network] = unsafe {
    &[
        Ipv4Network::new_unchecked(Ipv4Addr::new(127, 0, 0, 0), 8),
        Ipv4Network::new_unchecked(Ipv4Addr::new(10, 0, 0, 0), 8),
    ]
};

[achanda]

Thank, this is interesting. Is it possible for you to add some tests please?

[aurelilys]

Yes, of course, here are two tests added.