docstr: Timeout callback of _HTTPConnection instance.
  
  Raise a timeout HTTPError when a timeout occurs.
  
  :info string key: More detailed timeout information.
docstr_tok: ["Timeout","callback","of","_HTTPConnection","instance",".","Raise","a","timeout","HTTPError","when","a","timeout","occurs",".",":","info","string","key",":","More","detailed","timeout","information","."]
code: def _on_timeout(self, info=None):
      """Timeout callback of _HTTPConnection instance.
  
      Raise a timeout HTTPError when a timeout occurs.
  
      :info string key: More detailed timeout information.
      """
      self._timeout = None
      error_message = "Timeout {0}".format(info) if info else "Timeout"
      if self.final_callback is not None:
          raise HTTPError(599, error_message)
  
imports: from __future__ import absolute_import, division, print_function
  from tornado.escape import utf8, _unicode
  from tornado import gen
  from tornado.httpclient import HTTPResponse, HTTPError, AsyncHTTPClient, main, _RequestProxy
  from tornado import httputil
  from tornado.http1connection import HTTP1Connection, HTTP1ConnectionParameters
  from tornado.iostream import StreamClosedError
  from tornado.netutil import Resolver, OverrideResolver, _client_ssl_defaults
  from tornado.log import gen_log
  from tornado import stack_context
  from tornado.tcpclient import TCPClient
  from tornado.util import PY3
  import base64
  import collections
  import copy
  import functools
  import re
  import socket
  import sys
  from io import BytesIO
label_desc: Use image node_id 3 for calling the _HTTPConnection obj's underlying member method code with example usage: obj._on_timeout(info) without return types