docs: protected final void initialize(E exampleLeaf) {
      initializeCapacities(exampleLeaf);
  
      // create empty root
      createEmptyRoot(exampleLeaf);
  
      final Logging log = getLogger();
      if(log.isStatistics()) {
        String cls = this.getClass().getName();
        log.statistics(new LongStatistic(cls + ".directory.capacity", dirCapacity));
        log.statistics(new LongStatistic(cls + ".directory.minfill", dirMinimum));
        log.statistics(new LongStatistic(cls + ".leaf.capacity", leafCapacity));
        log.statistics(new LongStatistic(cls + ".leaf.minfill", leafMinimum));
      }
  
      initialized = true;
    }