You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: coser.go
    path of file: ./repos/ZeroBot-Plugin/plugin/coser
    
    the code of the file until where you have to start completion: // Package cos
    
func init() {
	p, err := setu.NewPool(setu.DefaultPoolDir,
		func(s string) (string, error) {
			if s != "coser" {
				return "", errors.New("invalid call")
			}
			typ := setu.DefaultPoolDir + "/" + "coser"
			if file.IsNotExist(typ) {
				err := os.MkdirAll(typ, 0755)
				if err != nil {
					return "", err
				}
			}
			data, err := web.RequestDataWith(web.NewDefaultClient(), coserURL, "GET", "", ua, nil)
			if err != nil {
				return "", err
			}
			arr := gjson.Get(helper.BytesToString(data), "data.data").Array()
			if len(arr) == 0 {
				return "", errors.New("data is empty")
			}
			pic := arr[rand.Intn(len(arr))]
			return pic.String(), nil
		}, web.GetData, time.Minute)
	if err != nil {
		panic(err)
	}
	control.AutoRegister(&ctrl.Options[*zero.Ctx]{
		DisableOnDefault: false,
		Brief:            "三次元coser",
		Help:             "- coser",
	}).ApplySingle(ctxext.DefaultSingle).OnFullMatch("coser").SetBlock(true).Limit(ctxext.LimitByGroup).
		Handle(func(ctx *zero.Ctx) {
			pic, err := p.Roll("coser")
			if err != nil {
				ctx.SendChain(message.Text("ERROR: ", err))
				return
			}
			if id := ctx.Send(message.Message{ctxext.FakeSenderForwardNode(ctx, message.Image("file:///"+file.BOTPATH+"/"+pic))}).ID(); id == 0 {
				ctx.SendChain(message.Text("ERROR: 可能被风控或下载图片用时过长，请耐心等待"))
			}
		})
}