https://clickhouse-test-reports.s3.yandex.net/19475/02d28c1f9b9558ca5af267167a542819b9e1d061/fuzzer_debug/report.html#fail1
{
    const std::string path = getPath();
    if (blocks.empty())
        return {};
    if (blocks.size() == 1)
    {
        OneBlockInputStream sorted_input(blocks.front());
        return flushToFile(path, sample_block, sorted_input, codec);
    }
    BlockInputStreams inputs;
    inputs.reserve(blocks.size());
    for (const auto & block : blocks)
        if (block.rows())
            inputs.push_back(std::make_shared<OneBlockInputStream>(block));
    MergingSortedBlockInputStream sorted_input(inputs, sort_description, rows_in_block);
    return flushToFile(path, sample_block, sorted_input, codec);
}
SortedBlocksWriter::PremergedFiles SortedBlocksWriter::premerge()