[Bug]: Missing attributes when using LocalBulkWriter

[Stevan1996]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

I am trying to use the LocalBulkWriter. When initializing the LocalBulkWriter, I get the following error message. I followed this user guide: https://milvus.io/docs/prepare-source-data.md

    writer = LocalBulkWriter(schema=schema, local_path=".", file_type=BulkFileType.JSON)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/steven/.conda/envs/dpm/lib/python3.11/site-packages/pymilvus/bulk_writer/local_bulk_writer.py", line 42, in __init__
    super().__init__(schema, chunk_size, file_type, **kwargs)
  File "/home/steven/.conda/envs/dpm/lib/python3.11/site-packages/pymilvus/bulk_writer/bulk_writer.py", line 57, in __init__
    if len(self._schema.fields) == 0:
           ^^^^^^^^^^^^^^^^^^^
AttributeError: 'function' object has no attribute 'fields'
Exception ignored in: <function LocalBulkWriter.__del__ at 0x707a78d6fba0>
Traceback (most recent call last):
  File "/home/steven/.conda/envs/dpm/lib/python3.11/site-packages/pymilvus/bulk_writer/local_bulk_writer.py", line 63, in __del__
    self._exit()
  File "/home/steven/.conda/envs/dpm/lib/python3.11/site-packages/pymilvus/bulk_writer/local_bulk_writer.py", line 67, in _exit
    if len(self._working_thread) > 0:
           ^^^^^^^^^^^^^^^^^^^^
AttributeError: 'LocalBulkWriter' object has no attribute '_working_thread'

Expected Behavior

No response

Steps/Code To Reproduce behavior

No response

Environment details

- pymilvus: 2.4.6
- protobuf: 5.28.2
- grpcio: 1.66.1

Anything else?

No response