hr, err := hash.NewReader(ctx, io.LimitReader(gr, part.Size), part.Size, "", "", part.ActualSize)
			if err != nil {
				return fmt.Errorf("decommissionObject: hash.NewReader() %w", err)
			}
			pi, err := z.PutObjectPart(ctx, bucket, objInfo.Name, res.UploadID,
				part.Number,
				NewPutObjReader(hr),
				ObjectOptions{
					PreserveETag: part.ETag, // Preserve original ETag to ensure same metadata.
					IndexCB: func() []byte {