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 __init__(self, key_l, delayed_tpl):
      self.key_l = key_l
      self.delayed_tpl = 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 1 to create a new DelayedDict object from inherited base classes: DelayedTask with example: obj = DelayedDict(key_l, delayed_tpl)