class_docstr: Base class for objects that periodically clean up timed-out waiters.
  
  Avoids memory leak in a common pattern like:
  
      while True:
          yield condition.wait(short_timeout)
          print('looping....')
class_docstr_tok: ["Base","class","for","objects","that","periodically","clean","up","timed-out","waiters",".","Avoids","memory","leak","in","a","common","pattern","like",":","while","True",":","yield","condition.wait","(","short_timeout",")","print","(","'looping","....","'",")"]
code: def __init__(self):
      self._waiters = collections.deque()  # Futures.
      self._timeouts = 0
  
imports: from __future__ import absolute_import, division, print_function
  import collections
  from tornado import gen, ioloop
  from tornado.concurrent import Future
label_desc: Use image node_id 1 to create a new _TimeoutGarbageCollector object from inherited base classes: object with example: obj = _TimeoutGarbageCollector()