addError method
Implementation
void addError(Object error, [StackTrace? stackTrace]) {
  assert(!isClosed, 'You cannot add error to closed Stream');
  _notifyError(error, stackTrace);
}void addError(Object error, [StackTrace? stackTrace]) {
  assert(!isClosed, 'You cannot add error to closed Stream');
  _notifyError(error, stackTrace);
}