actualReader, err := hash.NewReader(ctx, reader, size, md5hex, sha256hex, actualSize)
		if err != nil {
			writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL)
			return
		}
		if err = actualReader.AddChecksum(r, false); err != nil {
			writeErrorResponse(ctx, w, errorCodes.ToAPIErr(ErrInvalidChecksum), r.URL)
			return
		}
		opts.WantChecksum = actualReader.Checksum()

		// Set compression metrics.