code: def _set_request_context(
      route: str = "",
      request_id: str = "",
      app_name: str = "",
      multiplexed_model_id: str = "",
  ):
      """Set the request context. If the value is not set,
      the current context value will be used."""
  
      current_request_context = _serve_request_context.get()
      _serve_request_context.set(
          _RequestContext(
              route=route or current_request_context.route,
              request_id=request_id
              or current_request_context.request_id,
              app_name=app_name or current_request_context.app_name,
              multiplexed_model_id=multiplexed_model_id
              or current_request_context.multiplexed_model_id,
          )
      )
  
imports: import contextvars
  import logging
  from dataclasses import dataclass
  from typing import Callable, Optional
  import ray
  from ray.exceptions import RayActorError
  from ray.serve._private.client import ServeControllerClient
  from ray.serve._private.common import ReplicaTag
  from ray.serve._private.constants import SERVE_CONTROLLER_NAME, SERVE_NAMESPACE
  from ray.serve.exceptions import RayServeException
  from ray.serve.grpc_util import RayServegRPCContext
  from ray.util.annotations import DeveloperAPI
label_desc: Use image node_id 6 for calling a global function with example usage: _set_request_context(route, request_id, app_name, multiplexed_model_id) without return types