Method GetFragmentsAsyncImpl

cpp/src/arrow/dataset/dataset.cc:236–244

Default impl delegating the work to `GetFragmentsImpl` and wrapping it into BackgroundGenerator/TransferredGenerator, which offloads potentially IO-intensive work to the default IO thread pool and then transfers the control back to the specified executor.

// IO-intensive work to the default IO thread pool and then transfers the control
// back to the specified executor.
Result<FragmentGenerator> Dataset::GetFragmentsAsyncImpl(
    compute::Expression predicate, arrow::internal::Executor* executor) {
  ARROW_ASSIGN_OR_RAISE(auto iter, GetFragmentsImpl(std::move(predicate)));
  ARROW_ASSIGN_OR_RAISE(
      auto background_gen,
      MakeBackgroundGenerator(std::move(iter), io::default_io_context().executor()));
  auto transferred_gen = MakeTransferredGenerator(std::move(background_gen), executor);
  return transferred_gen;
}

struct VectorRecordBatchGenerator : InMemoryDataset::RecordBatchGenerator {
  explicit VectorRecordBatchGenerator(RecordBatchVector batches)