Wait on stop event when possible

Generally eliminate the `while True` loops while waiting for a stop
event and prefer to condition the loops on if the stop event is set,
blocking on that where it makes sense.  This generally comes in 3
flavors.  First and simplest, when there is a sleep and the stop event
is the only thing the loop blocks on, instead do a check using
`stop_event.wait(timeout)` to instead block on the stop event for the
designated amount of time. Second, when there is a different event that
is blocking in the loop, condition the loop on `stop_event.is_set()`
rather than breaking when it is set. Finally, when there is a separate
internal condition that requires a counter, have the loop iterate over
the counter and use `if stop_event.wait(timeout)` internal to the loop.

frigate/stats.py

@@ -94,12 +94,9 @@ class StatsEmitter(threading.Thread):
 
     def run(self):
         time.sleep(10)
-        while True:
-            if self.stop_event.is_set():
-                logger.info(f"Exiting watchdog...")
-                break
+        while not self.stop_event.wait(self.config.mqtt.stats_interval):
             stats = stats_snapshot(self.stats_tracking)
             self.mqtt_client.publish(
                 f"{self.topic_prefix}/stats", json.dumps(stats), retain=False
             )
-            time.sleep(self.config.mqtt.stats_interval)
+        logger.info(f"Exiting watchdog...")