Put uploads in threads

uploads_in_threads.py

zip_obj = s3_resource.Object("path/to/key.zip")
buffer = BytesIO(zip_obj.get()["Body"].read())
with ZipFile(buffer) as zipfile:
    with TransferManager(
        config=transfer_config,
        client=boto3.client("s3"),
    ) as transfer_manager:
        def _upload(file_name: str):
            dest_key = build_destination_key(file_name)
            transfer_manager.upload(
                fileobj=zipfile.open(file_name),
                key=dest_key,
                bucket="my_bucket"
            )
				
        with ThreadPool(
            processes=transfer_manager.config.max_submission_concurrency
        ) as pool:
            pool.imap_unordered(
                func=_upload,
                iterable=zipfile.namelist(),
                chunksize=chunk_size,
            )
            pool.join()