Fix

gradio/routes.py

@@ -610,12 +610,13 @@ async def stop_stream():
                 # For some reason tests are failing when using events only on CI
                 # so we use a different approach for CI but
                 # locally and in deployment we should use the event-based approach
-                while app.get_blocks().is_running:
-                    await asyncio.sleep(0.25)
-                return "stop"
-                # else:
-                #     await app.stop_event.wait()
-                #     return "stop"
+                if os.getenv("GRADIO_IS_E2E_TEST") and sys.version_info < (3, 9):
+                    while app.get_blocks().is_running:
+                        await asyncio.sleep(0.)
+                    return "stop"
+                else:
+                    await app.stop_event.wait()
+                    return "stop"
 
             async def iterator():
                 while True: