Method schema

cpp/src/arrow/dataset/scanner.cc:103–103

      : schema_(std::move(schema)), delegate_(std::move(delegate)) {}

  std::shared_ptr<Schema> schema() const override { return schema_; }
  Status ReadNext(std::shared_ptr<RecordBatch>* batch) override {
    ARROW_ASSIGN_OR_RAISE(auto next, delegate_.Next());
    if (IsIterationEnd(next)) {