type Config struct {
	Bucket          string
	Region          string
	Prefix          string
	ManifestsPrefix string
	BlobsPrefix     string
	Names           []string
	TouchRefresh    time.Duration
	EndpointURL     string
	AccessKeyID     string
	SecretAccessKey string
	SessionToken    string
	UsePathStyle    bool
}

type ReaderAtCloser interface {
	io.ReaderAt
	io.Closer
}