ServiceExtensionResponse.error(int _errorCode, String _errorDetail)

Source

ServiceExtensionResponse.error(this._errorCode, this._errorDetail)
    : _result = null {
  _validateErrorCode(_errorCode);
  if (_errorDetail is! String) {
    throw new ArgumentError.value(_errorDetail,
                                  "errorDetail",
                                  "Must be a String");
  }
}