TransportTest infrastructure doesn't allow restarting pumps #7330
Description
Describe the suggested improvement
Unfortunately, the transport test infrastructure is so rigid that it doesn't really allow you to properly restart pumps and wipe out the previous state. It also has built in assumptions around extracting the stack frame on the StartPump. StartPump fails if it is not the first await statement in a test, and restarting the pump would require to call StartPump multiple times.
Originally discussed on Particular/NServiceBus.AmazonSQS#2766
Additional Context
No response