[Core] Asynchronous Output Processor (#7049)

Co-authored-by: Alexander Matveev <alexm@neuralmagic.com>

vllm/worker/worker_base.py

@@ -263,6 +263,12 @@ class LocalOrDistributedWorkerBase(WorkerBase):
             broadcast_data.update(kwargs)
             broadcast_tensor_dict(broadcast_data, src=0)
 
+        if execute_model_req.output_proc_callback_fn:
+            model_input = dataclasses.replace(  # type: ignore
+                model_input,
+                output_proc_callback_fn=execute_model_req.
+                output_proc_callback_fn)
+
         return model_input, worker_input, kwargs
 
     def prepare_input(
@@ -289,7 +295,7 @@ class LocalOrDistributedWorkerBase(WorkerBase):
 
     def execute_model(
         self,
-        execute_model_req: Optional[ExecuteModelRequest] = None
+        execute_model_req: Optional[ExecuteModelRequest] = None,
     ) -> Optional[List[SamplerOutput]]:
         """Executes at least one model step on the given sequences, unless no
         sequences are provided."""