TypeError: cannot pickle '_thread.RLock' object

Hi I'm a newbie here, but when I kicked off this benchmark with Search Performance Test, I received the following error immediately. I tried to add some print statements, but couldn't zero in on the error. Appreciate any help. Thank you in advance!

2025-04-04 18:55:32,090 | INFO: Read the entire file into memory: test.parquet (dataset.py:247) (15253)
2025-04-04 18:55:32,116 | INFO: Read the entire file into memory: neighbors.parquet (dataset.py:247) (15253)
2025-04-04 18:55:32,162 | INFO: Start performance case (task_runner.py:147) (15253)
2025-04-04 18:55:32,162 | INFO: dropping old ------------- (task_runner.py:151) (15253)
2025-04-04 18:55:32,162 | INFO: task stage load ------------- (task_runner.py:153) (15253)  
2025-04-04 18:55:32,202 | WARNING: VectorDB load dataset error: cannot pickle '_thread.RLock' object (serial_runner.py:141) (15253)
2025-04-04 18:55:33,670 | WARNING: Failed to run performance case, reason = cannot pickle '_thread.RLock' object (task_runner.py:185) (15253)
Traceback (most recent call last):
  File "/home/ubuntu/ZillizVectorDBBench/vectordb_bench/backend/task_runner.py", line 154, in _run_perf_case
    _, load_dur = self._load_train_data()
                  ^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/ubuntu/ZillizVectorDBBench/vectordb_bench/backend/utils.py", line 43, in inner
    result = func(*args, **kwargs)
             ^^^^^^^^^^^^^^^^^^^^^
  File "/home/ubuntu/ZillizVectorDBBench/vectordb_bench/backend/task_runner.py", line 204, in _load_train_data
    raise e from None
  File "/home/ubuntu/ZillizVectorDBBench/vectordb_bench/backend/task_runner.py", line 202, in _load_train_data
    runner.run()
  File "/home/ubuntu/ZillizVectorDBBench/vectordb_bench/backend/runner/serial_runner.py", line 182, in run
    count, dur = self._insert_all_batches()
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/ubuntu/ZillizVectorDBBench/vectordb_bench/backend/utils.py", line 43, in inner
    result = func(*args, **kwargs)
             ^^^^^^^^^^^^^^^^^^^^^
  File "/home/ubuntu/ZillizVectorDBBench/vectordb_bench/backend/runner/serial_runner.py", line 142, in _insert_all_batches
    raise e from e
  File "/home/ubuntu/ZillizVectorDBBench/vectordb_bench/backend/runner/serial_runner.py", line 133, in _insert_all_batches
    count = future.result(timeout=self.timeout)
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/concurrent/futures/_base.py", line 456, in result
    return self.__get_result()
           ^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/concurrent/futures/_base.py", line 401, in __get_result
    raise self._exception
  File "/usr/lib/python3.12/multiprocessing/queues.py", line 264, in _feed
    obj = _ForkingPickler.dumps(obj)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.12/multiprocessing/reduction.py", line 51, in dumps
    cls(buf, protocol).dump(obj)
TypeError: cannot pickle '_thread.RLock' object

Start in vectordb_bench/backend/runner/serial_runner.py, especially _insert_all_batches, then follow the call path through task_runner.py and the Search Performance Test benchmark. Reproduce the load stage and trace the multiprocessing failure; done means the benchmark completes without the reported RLock pickling error.