resource

type Cache struct {
	Dir                   string
	HttpDo                func(req *http.Request) (*http.Response, error)
	Progress              Progress
	SkipAssetVerification bool
}

type Catalog struct {
	Items []Item
}

type Item struct {
	URL  string
	Name string
	MD5  string
	Size uint64
}

type Progress interface {
	io.Writer
	Start(total uint64)
	Add(add uint64)
	End()
}