presto-main/src/main/java/io/prestosql/operator/unnest/ArrayOfRowsUnnester.java/ArrayOfRowsUnnester/ArrayOfRowsUnnester
class ArrayOfRowsUnnester:    public ArrayOfRowsUnnester(RowType elementType)
    {
        super(Iterables.toArray(requireNonNull(elementType, "elementType is null").getTypeParameters(), Type.class));
        this.fieldCount = elementType.getTypeParameters().size();
        this.nullRowsEncountered = 0;
    }