This is a request to expose counters from /proc/net/stat/arp_cache, /proc/net/stat/rt_cache and /proc/net/stat/ndisc_cache on linux.

These stats are helpful in finding the root cause of a network issues.

I think it should be implemented with three different collectors: arpcache, routecache and ndisccache. But i might be wrong.
@SuperQ @pgier , what do you think about this?

I hope I can find some time to implement it.