private void ValidateApplication(IGoogleIdTokenInfo info, IList<string> errors)
 {
     if (info.AppIdentifier != expectedApplicationClientId)
     {
         errors.Add("This token is not valid for this application.");
     }
 }
        public IReadOnlyList<string> Validate(IGoogleIdTokenInfo info)
        {
            var errors = new List<string>();

            ValidateIssuer(info, errors);
            ValidateExpiry(info, errors);
            ValidateApplication(info, errors);

            return errors;
        }