[feat] Add return_routed_experts param to async_generate for parity with generate (#18508)

python/sglang/srt/entrypoints/engine.py

@@ -319,6 +319,7 @@ class Engine(EngineBase):
         lora_path: Optional[List[Optional[str]]] = None,
         custom_logit_processor: Optional[Union[List[str], str]] = None,
         return_hidden_states: bool = False,
+        return_routed_experts: bool = False,
         stream: bool = False,
         bootstrap_host: Optional[Union[List[str], str]] = None,
         bootstrap_port: Optional[Union[List[int], int]] = None,
@@ -358,6 +359,7 @@ class Engine(EngineBase):
             token_ids_logprob=token_ids_logprob,
             lora_path=lora_path,
             return_hidden_states=return_hidden_states,
+            return_routed_experts=return_routed_experts,
             stream=stream,
             custom_logit_processor=custom_logit_processor,
             bootstrap_host=bootstrap_host,