[router] leverage RAII to actively cancel request during client disconnect (#11399)

python/sglang/srt/entrypoints/grpc_server.py

@@ -211,13 +211,6 @@ class SGLangSchedulerServicer(sglang_scheduler_pb2_grpc.SglangSchedulerServicer)
             )
 
             async for output in response_generator:
-                # Check if client cancelled before processing/yielding
-                if context.cancelled():
-                    logger.info(f"Client cancelled request {request.request_id}")
-                    # Explicitly abort the request to notify scheduler
-                    await self.request_manager.abort_request(request.request_id)
-                    break
-
                 # Handle batch responses (for n>1 non-streaming)
                 if isinstance(output, list):
                     for batch_output in output: