Macro for_any_ip_version 

macro_rules! for_any_ip_version {
    ($ip_version:expr, $type_param:ident, $expression:expr) => { ... };
}

Evaluates expression for any given ip_version.

type_param will be defined to be crate::ip::Ipv4 for crate::ip::IpVersion::V4, and crate::ip::Ipv6 for crate::ip::IpVersion::V6.

Example usage:

let ip_version: IpVersion = foo();
for_any_ip_version!(ip_version, I, some_ip_generic_fn::<I>());