class_docstr: Error raised by SimpleAsyncHTTPClient on timeout.
  
  For historical reasons, this is a subclass of `.HTTPClientError`
  which simulates a response code of 599.
  
  .. versionadded:: 5.1
class_docstr_tok: ["Error","raised","by","SimpleAsyncHTTPClient","on","timeout",".","For","historical","reasons",",","this","is","a","subclass","of","`",".HTTPClientError","`","which","simulates","a","response","code","of","599",".","..","versionadded",":",":","5.1"]
code: def __init__(self, message: str) -> None:
      super().__init__(599, message=message)
  
imports: from tornado.escape import _unicode
  from tornado import gen, version
  from tornado.httpclient import HTTPResponse, HTTPError, AsyncHTTPClient, main, _RequestProxy, HTTPRequest
  from tornado import httputil
  from tornado.http1connection import HTTP1Connection, HTTP1ConnectionParameters
  from tornado.ioloop import IOLoop
  from tornado.iostream import StreamClosedError, IOStream
  from tornado.netutil import Resolver, OverrideResolver, _client_ssl_defaults, is_valid_ip
  from tornado.log import gen_log
  from tornado.tcpclient import TCPClient
  import base64
  import collections
  import copy
  import functools
  import re
  import socket
  import ssl
  import sys
  import time
  from io import BytesIO
  import urllib.parse
  from typing import Dict, Any, Callable, Optional, Type, Union
  from types import TracebackType
  import typing
label_desc: Use image node_id 1 to create a new HTTPTimeoutError object from inherited base classes: HTTPError with example: obj = HTTPTimeoutError(message)