Empty queue when changing the workload

[PeterTsayun]

Is your feature request related to a problem? Please describe:
For now, when changing the workload, we need to wait until the new queries are taken by the workers from the queue. This can cost some time, depending of the queue size, to see changes in the behavior of the database.

Please describe the solution you'd like:
Empty the worker queue when changing the workload.

Please describe alternatives you've considered:
Alternatives are welcome.

Affected Component(s):
WorkerPool

Additional context: