* Fix TUS offset queries in production environments
Previously, `mod_wsgi` would convert `HEAD` requests into `GET`, which
would be rejected, so clients were unable to resume an upload that failed
midway through.
To make use of this, update the SDK code to enable upload resumption.
* Add a test that forces a chunked TUS upload
* test_can_create_from_backup_in_chunks: make sure the upload is actually chunked
tqdm does not necessarily redraw the progress bar after every update,
and without the call to `refresh` it might not update it to the final state.
I discovered this while writing a test in which the progress bar is updated
in chunks, and the last chunk is smaller than the previous ones.
Roman Donchenko
Maxim Zhiltsov