presto-geospatial/src/main/java/io/prestosql/plugin/geospatial/SpatialPartitioningStateFactory.java/SpatialPartitioningStateFactory/getGroupedStateClass
class SpatialPartitioningStateFactory:    @Override
    public Class<GroupedSpatialPartitioningState> getGroupedStateClass()
    {
        return GroupedSpatialPartitioningState.class;
    }