Understanding the rationale behind a rule when trying to circumvent it

Callback functions for process and thread-related events must execute quickly without blocking because they're invoked during critical system operations while internal locks are held. Developers often circumvent these rules by queuing work to System Worker Threads but then blocking until completion, which defeats the purpose—the fundamental requirement is that the callback itself must return quickly, not just delegate work. Microsoft updated its documentation in 2020 to explicitly prohibit waiting on queued work items, as blocking indirectly (such as waiting on an event set by another thread) violates the spirit of the non-blocking requirement.