presto-main/src/main/java/io/prestosql/operator/TrackingLookupSourceSupplier.java/TrackingLookupSourceSupplier/getLookupSource
class TrackingLookupSourceSupplier:    static TrackingLookupSourceSupplier nonTracking(Supplier<LookupSource> lookupSourceSupplier)
    {
        requireNonNull(lookupSourceSupplier, "lookupSourceSupplier is null");
        return new TrackingLookupSourceSupplier()
        {
            @Override
            public LookupSource getLookupSource()
            {
                return lookupSourceSupplier.get();
            }

            @Override
            public OuterPositionIterator getOuterPositionIterator()
            {
                throw new UnsupportedOperationException();
            }
        };
    }