class_docstr: ColdStartProxy allows users to configure the load balancer to use a proxy service while the work is cold
  starting. This is useful with services that gets realtime requests but startup time for workers is high.
  
  If the request body is same and the method is POST for the proxy service,
  then the default implementation of `handle_request` can be used. In that case
  initialize the proxy with the proxy url. Otherwise, the user can override the `handle_request`
  
  Args:
      proxy_url (str): The url of the proxy service
code: def __init__(self, proxy_url: str):
      self.proxy_url = proxy_url
      self.proxy_timeout = 50
      if not asyncio.iscoroutinefunction(self.handle_request):
          raise TypeError("handle_request must be an `async` function")
  
imports: import asyncio
  from typing import Any
  from fastapi import HTTPException
  from pydantic import BaseModel
  from lightning.app.utilities.imports import _is_aiohttp_available, requires
label_desc: Use image node_id 1 to create a new ColdStartProxy object  with example: obj = ColdStartProxy(proxy_url)