Method ProcessFirstBuffer

cpp/src/arrow/csv/reader.cc:1089–1103

 protected:
  Future<std::shared_ptr<Buffer>> ProcessFirstBuffer() {
    // First block
    auto first_buffer_future = buffer_generator_();
    return first_buffer_future.Then(
        [self = shared_from_this()](const std::shared_ptr<Buffer>& first_buffer)
            -> Result<std::shared_ptr<Buffer>> {
          if (first_buffer == nullptr) {
            return Status::Invalid("Empty CSV file");
          }
          std::shared_ptr<Buffer> first_buffer_processed;
          RETURN_NOT_OK(self->ProcessHeader(first_buffer, &first_buffer_processed));
          RETURN_NOT_OK(self->MakeColumnBuilders());
          return first_buffer_processed;
        });
  }

  Executor* cpu_executor_;
  AsyncGenerator<std::shared_ptr<Buffer>> buffer_generator_;