class_docstr: Simple cached property with classvar.
class_docstr_tok: ["Simple","cached","property","with","classvar","."]
code: def __init__(self):
      self.lock = threading.RLock()
  
imports: import concurrent.futures
  import sys
  import threading
  import pytest
  from flash.core.serve._compat.cached_property import cached_property
  from flash.core.utilities.imports import _TOPIC_SERVE_AVAILABLE
label_desc: Use image node_id 1 to create a new CachedCostItem object  with example: obj = CachedCostItem()