private void PasswordDialog_FormClosed(object sender, FormClosedEventArgs e)
 {
     if (textBox1.Text == "")
     {
         AuthenticationFinished?.Invoke(true);
     }
     else
     {
         AuthenticationFinished?.Invoke(false);
     }
 }
        public async Task <bool> AuthenticateAsync(string username, string password)
        {
            var url     = $"{baseUrl}api-token-auth/";
            var details = new TangentLoginDetails {
                username = username, password = password
            };

            Token = await LoginAsync(url, details);

            AuthenticationFinished?.Invoke(this, e);
            return(IsAuthenticated);
        }