Fix end_session() to handle server errors immediately

The server currently does not support session.finish event for
qwen3.5-omni-flash-realtime, returning an error instead of
session.finished. Previously end_session() would wait the full
timeout duration (20s) before falling back to ws.close().

Now the method detects server error events immediately and closes
the connection without waiting, reducing wait time from 20s to
<0.1s when the server rejects session.finish.

Related to issue #140

Author: zhansheng.lzs

dashscope/audio/qwen_omni/omni_realtime.py

@@ -153,6 +153,7 @@ def __init__(
         self.metrics = []
         # Add event for synchronously waiting on connection close
         self.disconnect_event = None
+        self._disconnect_error = None
 
     def _generate_event_id(self):
         """
@@ -350,6 +351,7 @@ def end_session(self, timeout: int = 20) -> None:
 
         # create the event
         self.disconnect_event = threading.Event()
+        self._disconnect_error = None
 
         self.__send_str(
             json.dumps(
@@ -362,10 +364,14 @@ def end_session(self, timeout: int = 20) -> None:
 
         # wait for the event to be set
         finish_success = self.disconnect_event.wait(timeout)
-        # clear the event
+        error = self._disconnect_error
         self.disconnect_event = None
+        self._disconnect_error = None
 
-        # if the event is not set, close the connection
+        # if the server returned an error or timed out, close the connection
+        if error is not None:
+            self.close()
+            return
         if not finish_success:
             self.close()
             raise TimeoutError(
@@ -536,6 +542,14 @@ def _on_message(  # pylint: disable=unused-argument,too-many-branches
                         logger.info("[omni realtime] session finished")
                         if self.disconnect_event is not None:
                             self.disconnect_event.set()
+                    elif "error" == json_data.get("type"):
+                        if self.disconnect_event is not None:
+                            self._disconnect_error = json_data.get("error")
+                            logger.warning(
+                                "[omni realtime] error during end_session: %s",
+                                self._disconnect_error,
+                            )
+                            self.disconnect_event.set()
                     if "response.created" == json_data["type"]:
                         self.last_response_id = json_data["response"]["id"]
                         self.last_response_create_time = time.time() * 1000