DevTest does not support the concept of sending unsolicited HTTP responses.
So by sending the second response, do you mean
- the VSM Responder step sends the 1st response to the consumer,
- the VSM waits 10 seconds,
- then the VSM executes an HTTP or REST Step to send a request (which is response 2 of 2) to an endpoint after 10 seconds?
The below is a non-working example of a VSM that does the above. The key is that the sending of the 2nd response is really an HTTP Request (not response) to an endpoint.
Does this solve for your requirement?