presto-main/src/main/java/io/prestosql/execution/buffer/PagesSerdeUtil.java/PagesSerdeUtil/writeRawPage
class PagesSerdeUtil:    static void writeRawPage(Page page, SliceOutput output, BlockEncodingSerde serde)
    {
        output.writeInt(page.getChannelCount());
        for (int channel = 0; channel < page.getChannelCount(); channel++) {
            writeBlock(serde, output, page.getBlock(channel));
        }
    }