long stop = stopwatch.elapsedMillis();
System.out.printf("[%,d]: insert = %,d ms%n", numPoints, stop);
stopwatch.reset().start();
ImmutableRTree searchTree = ImmutableRTree.newImmutableFromMutable(tree);
stop = stopwatch.elapsedMillis();
System.out.printf("[%,d]: size = %,d bytes%n", numPoints, searchTree.toBytes().length);
System.out.printf("[%,d]: buildImmutable = %,d ms%n", numPoints, stop);
stopwatch.reset().start();