如何在OAuth2令牌中包含发卡行字段

I'm trying to build an OAuth2 server. My access token (jwt type) server give me doesn't have iss (issuer) field. How can I add it to my token and another fields in payload? This is my server config and token server give me

Token image

I tried to find is api docs but I found nothing i tried config here https://go-oauth2.github.io/ but looklike "manager.MapTokenModel(models.NewToken())" doesn't work anymore, I dont know if it can help me

manager = manage.NewDefaultManager()

    cfg := &manage.Config{
        // access token expiration time
        AccessTokenExp: time.Hour * 2,
        // refresh token expiration time
        RefreshTokenExp: time.Hour * 24 * 3,
        // whether to generate the refreshing token
        IsGenerateRefresh: true,
    }

    manager.SetAuthorizeCodeTokenCfg(cfg)
    manager.SetAuthorizeCodeExp(time.Minute * 30)

    manager.MapAuthorizeGenerate(generates.NewAuthorizeGenerate())
    // generate jwt access token
    manager.MapAccessGenerate(generates.NewJWTAccessGenerate([]byte("12345678"), jwt.SigningMethodHS256))

    manager.MustTokenStorage(store.NewMemoryTokenStore())

    clientStore = store.NewClientStore()
    manager.MapClientStorage(clientStore)

    srv = server.NewDefaultServer(manager)
    srv.SetAllowGetAccessRequest(true)
    // allow the grant types model:AuthorizationCode,PasswordCredentials,ClientCredentials,Refreshing
    srv.SetAllowedGrantType("authorization_code")
    // get client id and secrect, this is default handler
    srv.SetClientInfoHandler(server.ClientFormHandler)
    // way to get user ID
    srv.SetUserAuthorizationHandler(userAuthorizeHandler)
    //
    srv.SetExtensionFieldsHandler(extensionFieldsHanler)
    manager.SetRefreshTokenCfg(manage.DefaultRefreshTokenCfg)

    srv.SetInternalErrorHandler(func(err error) (re *errors.Response) {
        log.Println("Internal Error:", err.Error())
        return
    })

    srv.SetResponseErrorHandler(func(re *errors.Response) {
        log.Println("Response Error:", re.Error.Error())
    })

So I need some way to add more filed to my token.