fix session closed

src/common/tcp_connector.py

@@ -3,11 +3,7 @@ import certifi
 import aiohttp
 
 ssl_context = ssl.create_default_context(cafile=certifi.where())
-connector = None
 
 
 async def get_tcp_connector():
-    global connector
-    if connector is None:
-        connector = aiohttp.TCPConnector(ssl=ssl_context)
-    return connector
+    return aiohttp.TCPConnector(ssl=ssl_context)