presto-geospatial-toolkit/src/main/java/io/prestosql/geospatial/KdbTree.java/KdbTree/findIntersectingLeaves
class KdbTree:    public Map<Integer, Rectangle> findIntersectingLeaves(Rectangle envelope)
    {
        ImmutableMap.Builder<Integer, Rectangle> leaves = ImmutableMap.builder();
        addLeaves(root, leaves, node -> node.extent.intersects(envelope));
        return leaves.build();
    }