ZMQ communication layer

[AmineDiro]

After multiple tests to profile the batch_submit method performance, I saw that bottleneck is the serialization in the distibuted.protocol . Basically when calling an attribute in an actor we use the RPCPool to send a send_recv call on communication layer which calls in return the protocol.dumps().

Msg size : 717
Protocol serialization : into list of 100002 protocol frames took 5.31s
Simple  cloudpickle.dumps() of message took 0.12s

This is too slow when submitting millions of tasks + I can optimize the storage layer to directly deal with serialized message.

I'll test using ZMQ for communication between client <-> QueuePool and Queue<-> workers.