This allows a small wrapper class to be written
```py
class AsyncEventQueue:
def __init__(self, events):
self._events = events
async def __await__(self):
yield asyncio.core._io_queue.queue_read(self._events)
return self._events.get()
def __enter__(self):
return self
def __exit__(self, exc_type, exc_value, traceback):
pass
```
and used to just "await" the next event:
```py
async def key_task():
print("waiting for keypresses")
with keypad.KeyMatrix([board.D4], [board.D5]) as keys, AsyncEventQueue(keys.events) as ev:
while True:
print(await ev)
```
Because checking the empty status of the EventQueue does not enter
CircuitPython bytecode, it's assumed (but not measured) that this is
more efficient than an equivalent loop with an `await async.sleep(0)`
yield and introduces less latency than any non-zero sleep value.
Jeff Epler
Neradoc
Scott Shawcroft
Dan Halbert
Jeff Epler