Background callback not working with boto3 connection, objc[54693]: +[__NSCFConstantString initialize] may have been in progress in another thread when fork() was called

[pengz]

Hi there, I tried to download some s3 files in a background callback triggered by a button click, however, I am having error when connecting to boto3 s3 client
s3 = boto3.client( "s3", aws_access_key_id=ACCESS_KEY, aws_secret_access_key=SECRET_KEY, )

I tried export OBJC_DISABLE_INITIALIZE_FORK_SAFETY=YES,
set the app.run_server to threaded=True or processes=4 all doesn’t work, I would like some help on any ideas or directions on how to solve it, thank you