res, err := er.NewMultipartUpload(ctx, bucket, object, ropts)
	if err != nil {
		return setRestoreHeaderFn(oi, err)
	}

	var uploadedParts []CompletePart
	var rs *HTTPRangeSpec
	// get reader from the warm backend - note that even in the case of encrypted objects, this stream is still encrypted.
	gr, err := getTransitionedObjectReader(ctx, bucket, object, rs, http.Header{}, oi, opts)
	if err != nil {