How and why the leap second affected Cloudflare DNS
https://blog.cloudflare.com/how-and-why-the-leap-second-affected-cloudflare-dns/ [blog.cloudflare.com]
2017-01-02 17:12
Time goes backward, and then the real fun starts.
Half the blame is on go, for not providing a monotonic clock. But I’d say the other half is repeating a second. Don’t have this problem if you ignore the leap second. :)