r, err := hash.NewReader(ctx, bytes.NewReader(b.data), int64(len(b.data)), "", "", int64(len(b.data)))
		bugLogIf(ctx, err)
		custom := b.headerKV()
		_, err = er.putMetacacheObject(ctx, o.objectPath(b.n), NewPutObjReader(r), ObjectOptions{
			UserDefined: custom,
		})
		if err != nil {
			mc.setErr(err.Error())
			cancel()
			return err
		}
		if b.n == 0 {
			return nil