New Feature Idea: Debounce expensive events by providing `EventBus.get_or_dispatch(SomeEvent, include=..., exclude=...)`

[pirate]

Helpful for debouncing slow expensive events, before firing a new one you can check if any recent event is good enough and use that instead.

async def debounced_screenshot(target_id: str) -> bytes:
	"""gets the most recent screenshot within last 5 seconds or takes a new one"""

	is_fresh = lambda e: e.event_completed_at < (datetime.now() - timedelta(seconds=5))
    is_irrelevant = lambda e: e.target_id != target_id or e.event_status != 'completed'

    recent_or_new_screenshot = event_bus.get_or_dispatch(
		ScreenshotEvent(target_id=target_id, full_page=True),
		include=is_fresh,
        exclude=is_irrelevant,
    )

    # will check for any ScreenshotEvent in `event_bus.event_history` (up to history_max_length most recent events)
    # that matches the include & exclude criteria and return most recent one if any are found
    # otherwise will dispatch a new event and return that

    return (await recent_or_new_screenshot.event_result())

This should allow you to call debounced_screenshot(...) many times in a short timeframe while ratelimiting the actual pace of screenshots to 1x/5s.