class_docstr: DelayedDict.
  It is designed for following feature:
  Converting following existing code to parallel
  - constructing a dict
  - key can be gotten instantly
  - computation of values tasks a lot of time.
      - AND ALL the values are calculated in a SINGLE function
code: def get_delayed_tuple(self):
      return self.delayed_tpl
  
imports: from functools import partial
  from threading import Thread
  from typing import Callable, Text, Union
  from joblib import Parallel, delayed
  from joblib._parallel_backends import MultiprocessingBackend
  import pandas
  from queue import Queue
  import concurrent
  from qlib.config import C, QlibConfig
label_desc: Use image node_id 2 for calling the DelayedDict obj's underlying member method code with example usage: obj.get_delayed_tuple() and returns: self