class_docstr: A non-blocking TCP connection factory.
  
  .. versionchanged:: 5.0
     The ``io_loop`` argument (deprecated since version 4.1) has been removed.
code: def close(self) -> None:
      if self._own_resolver:
          self.resolver.close()
  
imports: import functools
  import socket
  import numbers
  import datetime
  import ssl
  import typing
  from tornado.concurrent import Future, future_add_done_callback
  from tornado.ioloop import IOLoop
  from tornado.iostream import IOStream
  from tornado import gen
  from tornado.netutil import Resolver
  from tornado.gen import TimeoutError
  from typing import Any, Union, Dict, Tuple, List, Callable, Iterator, Optional
label_desc: Use image node_id 2 for calling the TCPClient obj's underlying member method code with example usage: obj.close() without return types