public string PostRedirect([FromForm] Data.Users.Body body)
        {
            var handler = new JwtSecurityTokenHandler();
            var token   = handler.ReadToken(body.id_token) as JwtSecurityToken;

            body.user = token.Subject;
            Users.Tokens.TryRemove(body.state, out var old);
            Users.Tokens.TryAdd(body.state, (body, DateTime.UtcNow));
            return("SignIn Success. Please return to the app.");
        }
        public string GetCheck(string State)
        {
            Data.Users.Body body = null;

            if (string.IsNullOrEmpty(State))
            {
                body       = new Data.Users.Body();
                body.error = "Not Found";
                return(JsonConvert.SerializeObject(body));
            }
            if (Users.Tokens.TryRemove(State, out var keypair) == true)
            {
                body = keypair.Item1;
            }

            if (body == null)
            {
                body       = new Data.Users.Body();
                body.error = "Not Found";
            }

            return(JsonConvert.SerializeObject(body));
        }