In the composer, we already only allow for S3 multipart uploads
if enable_direct_s3_uploads is true, so in the backups uploader
that is based on Uppy we want to do the same thing. In future
if self-hosters need some way to not use S3 multipart in these
scenarios for whatever reason we can revisit this then (which
should be as simple as adding a enable_multipart_s3_uploads site
setting).
Martin Brennan
40d13ce662