@Override
  public String toString() {
    StringBuilder s = new StringBuilder();
    int2ObjectEntrySet().fastForEach(entry -> {
      s.append(s.length() == 0 ? "" : ", ").append(Key.getKeyByIndex(entry.getIntKey())).append(" -> ").append(entry.getValue());
    });
    return "[" + s + "]";
  }
@Override
  public String toString()