presto-main/src/main/java/io/prestosql/operator/PagesSpatialIndexSupplier.java/PagesSpatialIndexSupplier/get
class PagesSpatialIndexSupplier:    @Override
    public PagesSpatialIndex get()
    {
        if (rtree.isEmpty()) {
            return EMPTY_INDEX;
        }
        return new PagesRTreeIndex(session, addresses, types, outputChannels, channels, rtree, radiusChannel, spatialRelationshipTest, filterFunctionFactory, partitions);
    }