class_docstr: A helper class for managing pool of workers.
class_docstr_tok: ["A","helper","class","for","managing","pool","of","workers","."]
docstr: Schedule a func to be run
code: def apply_async(self, func, callback=None):
      """Schedule a func to be run"""
      return self._pool.apply_async(
          SafeFunction(func), callback=callback
      )
  
imports: import gc
  import os
  import sys
  import warnings
  import threading
  from abc import ABCMeta, abstractmethod
  from .format_stack import format_exc
  from .my_exceptions import WorkerInterrupt, TransportableException
  from ._multiprocessing_helpers import mp
  from ._compat import with_metaclass
label_desc: Use image node_id 3 for calling the PoolManagerMixin obj's underlying member method code with example usage: obj.apply_async(func, callback) and returns: self