code: def deploy_proxy_replicas():
      # Deploy a special proxy deployment replica on each node
      # to guarantee that the http proxy actor runs on each node
      # even when the node has zero echo deployment replicas.
      # This is needed since later on wrk will send requests to
      # the http proxy on each node.
      @serve.deployment(
          name="proxy",
          num_replicas=len(ray.nodes()),
          ray_actor_options={"num_cpus": 0, "resources": {"proxy": 1}},
      )
      class Proxy:
          def __call__(self, request):
              return "Proxy"
  
      serve.run(Proxy.bind(), name="proxy", route_prefix="/proxy")
  
file_path: ray/release/serve_tests/workloads/autoscaling_single_deployment.py
imports: import click
  import json
  import logging
  import math
  import os
  import ray
  from ray import serve
  from serve_test_utils import aggregate_all_metrics, run_wrk_on_all_nodes, save_test_results, is_smoke_test
  from serve_test_cluster_utils import setup_local_single_node_cluster, setup_anyscale_cluster, warm_up_one_cluster, NUM_CPU_PER_NODE, NUM_CONNECTIONS
  from typing import Optional
label_desc: Use image node_id 2 for calling a global function with example usage: deploy_proxy_replicas() and returns: str