Remove sleep from pull-based event loop

[Dandandan]

Is your feature request related to a problem or challenge? Please describe what you are trying to do.

The current implementation sleeps (currently ~100ms) whenever there is no job active. This adds some extra latency to the jobs. We could instead have the scheduler send a message to the executor that a new tasks are available.

Describe the solution you'd like have the scheduler send a message to the executor that tasks are available. remove sleeping logic from poll_loop (e.g. implement with mutex)

Describe alternatives you've considered A clear and concise description of any alternative solutions or features you've considered.

Additional context Add any other context or screenshots about the feature request here.