Hey @iffiX, thanks a lot for sharing the exciting project!! We will certainly study and share with other team members. 
Regarding tests for delay/drop/retry messages, @osalpekar implemented a faulty agent 1 for that purpose, and the majority of faulty tests can be found here 1.

So do you know any python libraries such as DEMi, fuzzowski which can simulate a connection layer and let users  send & recv ,  shift, reorder & delay ,  poke & inspect  messages? Since I need to simulate the RPC layer, these two libraries metioned above are not appropriate for this task.

If this is just for simulating RPCs, does mock work in this case? Sth like this 1.
Also cc TensorPipe expert @lcw, do you know any good tools for this purpose?