presto-main/src/main/java/io/prestosql/operator/ScanFilterAndProjectOperator.java/ScanFilterAndProjectOperator/getUpdatablePageSourceSupplier
class ScanFilterAndProjectOperator:    @Override
    public Supplier<Optional<UpdatablePageSource>> getUpdatablePageSourceSupplier()
    {
        return () -> {
            if (pageSource instanceof UpdatablePageSource) {
                return Optional.of((UpdatablePageSource) pageSource);
            }
            return Optional.empty();
        };
    }