#264 Fix working load start delay

[Robert McMahon]

--working-load needs to have a start delay so one can more easily see how a working load impacts and established low latency traffic stream

[Jean Tourrilhes]

In my case, the working loads have different sources and sinks than the tested traffic, so I need to do it in the experimentation framework itself (bunch of python scripts). And I get a lot more flexibility in term configuring those parallel iperf sessions (or MGEN). So, personally, I'm not seeing myself ever using the workload feature in this project.
I think the workload feature is great for simple usecases, a good question for you is how much complexity you put into it and what's the limit. For example, what about on-off periodic workload ? Or Poisson traffic ?

[Robert McMahon]

There is the flows code too. Have you tried it? It's based on python's asyncio and ssh.

I've thought about weighted graphs for both writes and delays for the working load. That probably would be the way to realize different patterns. There is the periodic-burst option which probably could be generalzed too.