presto-spi/src/main/java/io/prestosql/spi/block/AbstractRowBlock.java/AbstractRowBlock/AbstractRowBlock
class AbstractRowBlock:    protected AbstractRowBlock(int numFields)
    {
        if (numFields <= 0) {
            throw new IllegalArgumentException("Number of fields in RowBlock must be positive");
        }
        this.numFields = numFields;
    }