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