Method ScanBatchesAsync

cpp/src/arrow/dataset/file_test.cc:394–406

        num_batches_(num_batches) {}

  Result<RecordBatchGenerator> ScanBatchesAsync(
      const std::shared_ptr<ScanOptions>& options) override {
    // Fragment with start_=0 defers returning the generator
    if (start_ == 0) {
      std::this_thread::sleep_for(std::chrono::duration<double>(0.1));
    }

    auto vec = gen::Gen({gen::Step(start_)})
                   ->FailOnError()
                   ->RecordBatches(rows_per_batch_, num_batches_);
    auto it = MakeVectorIterator(vec);
    return MakeBackgroundGenerator(std::move(it), io::default_io_context().executor());
  }

  std::string type_name() const override { return "mock"; }