I had head-of-line-blocking issues recently on a 10 Gbps data centre link! HTTP client packages often use a small, fixed number of connections per domain. So i

I had head-of-line-blocking issues recently on a 10 Gbps data centre link! HTTP client packages often use a small, fixed number of connections per domain. So if you have two servers talking to each other and there's slow requests mixed in with short RPCs, the latter can sit in a queue for tens of seconds.