}
	ok, err := clnt.BucketExists(r.Context(), bucket)
	if err != nil {
		return nil, err
	}
	if !ok {
		return nil, os.ErrNotExist
	}

	pr, pw := io.Pipe()

	wa := &writerAt{
		buffer: make(map[int64][]byte),
		w:      pw,
		r:      pr,
		wg:     &sync.WaitGroup{},
	}
	wa.wg.Add(1)
	go func() {
		_, err := clnt.PutObject(r.Context(), bucket, object, pr, -1, minio.PutObjectOptions{