pub fn normalize_ip(ip: IpAddr) -> IpAddr
Normalise an IP address: IPv4-mapped IPv6 addresses (::ffff:A.B.C.D) are converted to their plain IPv4 form so that 10.0.0.1 and ::ffff:10.0.0.1 produce the same FlowKey.
::ffff:A.B.C.D
10.0.0.1
::ffff:10.0.0.1
FlowKey