add balance

managers/background_tasks.py

@@ -116,21 +116,16 @@ class BackgroundTaskManager:
         Returns:
             Number of tasks cancelled
         """
-        cancelled = 0
-        
         async with self._lock:
-            for task in list(self._tasks.values()):
-                if not task.done():
-                    task.cancel()
-                    try:
-                        await task
-                    except asyncio.CancelledError:
-                        pass
-                    cancelled += 1
-            
+            running = [t for t in self._tasks.values() if not t.done()]
+            for task in running:
+                task.cancel()
+            if running:
+                await asyncio.gather(*running, return_exceptions=True)
             self._tasks.clear()
             self._task_info.clear()
-        
+
+        cancelled = len(running)
         logger.info(f"All tasks cancelled: {cancelled}")
         return cancelled