Number of concurrent threads to download files (1 thread = 1 file download).
Defaults to 8.
tqdm_class (`tqdm`, *optional*):
If provided, overwrites the default behavior for the progress bar. Passed
argument must inherit from `tqdm.auto.tqdm` or at least mimic its behavior.
Note that the `tqdm_class` is not passed to each individual download.
Defaults to the custom HF progress bar that can be disabled by setting
`HF_HUB_DISABLE_PROGRESS_BARS` environment variable.