wall: load balancer brick

[jerome-jutteau]

The idea is to distribute traffic from a single input edge to several output edge (round robin). Traffic coming back from all output edge is sent to input edge

Example of scenario of an application on several cores:

       ________________
       |               |
       |               +--[queue1.a] ~ [queue1.b]--[rxtx1]  } graph1 on CPU core 1
       |               |
[nic]--+ load balancer +--[queue2.a] ~ [queue2.b]--[rxtx2]  } graph2 on CPU core 2
       |               |
       |               +--[queue3.a] ~ [queue3.b]--[rxtx3]  } graph3 on CPU core 3
       |_______________|

|-------graph0 on CPU core 0-------|