presto-geospatial-toolkit/src/main/java/io/prestosql/geospatial/KdbTree.java/KdbTree/buildKdbTree
class KdbTree:    public static KdbTree buildKdbTree(int maxItemsPerNode, Rectangle extent, List<Rectangle> items)
    {
        checkArgument(maxItemsPerNode > 0, "maxItemsPerNode must be > 0");
        requireNonNull(extent, "extent is null");
        requireNonNull(items, "items is null");
        return new KdbTree(buildKdbTreeNode(maxItemsPerNode, 0, extent, items, new LeafIdAllocator()));
    }