Function MakeDefaultIfEmptyGenerator

cpp/src/arrow/util/async_generator.h:2067–2069

/// This generator is async-reentrant.
template <typename T>
AsyncGenerator<T> MakeDefaultIfEmptyGenerator(AsyncGenerator<T> source, T or_value) {
  return DefaultIfEmptyGenerator<T>(std::move(source), std::move(or_value));
}
}  // namespace arrow