How do I load test async response?

I am developing a bot application, using LUIS and MS Bot Framework, written in Node.js.

I am trying to load test my bot but the problem is that LUIS response is Async, which means my load test must be able to receive new incoming connection some time after the initial request.

Which framework would be able to handle this? I looked at the following and none seem to be able to do it: JMeter, Dimon, Artillery, Bot Framework Load Testing.

EDIT: What about QMetry? Anyone having experience can comment on its feasibility?