presto-main/src/main/java/io/prestosql/operator/OuterLookupSource.java/OuterLookupSource/createOuterLookupSourceSupplier
class OuterLookupSource:    public static TrackingLookupSourceSupplier createOuterLookupSourceSupplier(Supplier<LookupSource> lookupSourceSupplier)
    {
        return new OuterLookupSourceSupplier(lookupSourceSupplier);
    }