Claims-Based authentication in MVC Core

public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory) {
    //略
    app.UseCookieAuthentication(new CookieAuthenticationOptions()
    {
      AuthenticationScheme = "MyCoodieMiddlewareInstance",
      LoginPath = new PathString(),
      AccessDeniedPath = new PathString(),
      AutomaticAuthenticate = true,
      AutomaticChallenge = true
    });
}

var myclaims = new List<Claim>(new Claim[] { new Claim("Id", user.Id.ToString())});
var claimsPrincipal = new ClaimsPrincipal(new ClaimsIdentity(myclaims, "MyCookieMiddlewareInstance"));
HttpContext.Authentication.SignInAsync("MyCookieMiddlewareInstance", claimPrincipal).Wait();

HttpContext.Authentication.SignOutAsync("MyCookieMiddlewareInstance").Wait();

var userId = User.FindFirst("Id").Value;