Refactor execution priority to use a counter for microtask and delayed events

[caduandrade]

Replace the ExecutionPriority enum (low and high) with an integer counter to manage the balance between microtask and Future.delayed during event execution:

• 0: Always use microtask.
• 1: Alternate between microtask and Future.delayed.
• N > 1: Execute N events with microtask before using Future.delayed.

This change aims to provide finer control over the balance between performance and UI responsiveness, improving flexibility for different use cases.