address PR comments

bumble/device.py

@@ -1245,7 +1245,7 @@ class Device(CompositeEventEmitter):
 
     async def power_off(self) -> None:
         if self.powered_on:
-            await self.host.reset()
+            await self.host.flush()
             self.powered_on = False
 
         # TODO: more cleanup

bumble/utils.py

@@ -20,7 +20,7 @@ import logging
 import traceback
 import collections
 import sys
-from typing import Awaitable, TypeVar
+from typing import Awaitable, Set, TypeVar
 from functools import wraps
 from pyee import EventEmitter
 
@@ -157,6 +157,9 @@ class AsyncRunner:
     # Shared default queue
     default_queue = WorkQueue()
 
+    # Shared set of running tasks
+    running_tasks: Set[Awaitable] = set()
+
     @staticmethod
     def run_in_task(queue=None):
         """
@@ -187,6 +190,19 @@ class AsyncRunner:
 
         return decorator
 
+    @staticmethod
+    def run(coroutine):
+        """
+        Create a task to run a coroutine in a "fire and forget" task.
+
+        Using this method instead of just calling `asyncio.create_task(coroutine)`
+        is necessary when you don't keep a reference to the task, because `asyncio`
+        only keeps weak references to alive tasks.
+        """
+        task = asyncio.create_task(coroutine)
+        AsyncRunner.running_tasks.add(task)
+        task.add_done_callback(AsyncRunner.running_tasks.remove)
+
 
 # -----------------------------------------------------------------------------
 class FlowControlAsyncPipe: