presto-spi/src/main/java/io/prestosql/spi/block/SingleRowBlockWriter.java/SingleRowBlockWriter/getSizeInBytes
class SingleRowBlockWriter:    @Override
    public long getSizeInBytes()
    {
        long currentBlockBuilderSize = 0;
        for (BlockBuilder fieldBlockBuilder : fieldBlockBuilders) {
            currentBlockBuilderSize += fieldBlockBuilder.getSizeInBytes();
        }
        return currentBlockBuilderSize - initialBlockBuilderSize;
    }