add event handling sample

docs/ten_framework/ten_packages/python_async_extension.md

@@ -51,6 +51,45 @@ class DefaultAsyncExtension(AsyncExtension):
 
 Each method simulates a delay using `await asyncio.sleep()`.
 
+## FAQ
+
+### Aysnc loop for event handling
+
+- Create a queue: use `asyncio.Queue`.
+- Create an async task for event handling.
+
+Here is the sample code:
+
+```python
+import asyncio
+from ten import AsyncExtension, AsyncTenEnv
+
+class DefaultAsyncExtension(AsyncExtension):
+    queue = asyncio.Queue()
+    loop:asyncio.AbstractEventLoop = None
+
+    async def on_start(self, ten_env: AsyncTenEnv) -> None:
+        self.loop = asyncio.get_event_loop()
+
+        self.loop.create_task(self._consume())
+
+    async def on_stop(self, ten_env: AsyncTenEnv) -> None:
+        self.queue.put(None)
+
+    async def _consume(self) -> None:
+        while True
+            try:
+                value = await self.queue.get()
+                if value is None:
+                    self.ten_env.log_info("async loop exit")
+                    break
+
+                # Code for processing values retrieved from the queue.
+
+            except Exception as e:
+                self.ten_env.log_error(f"Failed to handle {e}")
+```
+
 ## Conclusion
 
 TEN's Python async extension provide a powerful way to handle long-running tasks asynchronously. By integrating Python’s `asyncio` framework, the extensions ensure that operations such as network calls or file handling are efficient and non-blocking. This makes TEN a great choice for building scalable, modular applications with asynchronous capabilities.