docs: private void stats(long started) {
          long used;
  
          System.out.println();
          usedMemory();
          runGC();
          // CAUTION: I need a println before the next "used" call to get accurate numbers!?
          System.out.println("  ms:          " + (System.currentTimeMillis() - started));
          used = usedMemory();
          engine.free();
          runGC();
          System.out.println("  mem:         " + (used - usedMemory()));
          System.out.println();
          System.out.println();
      }