code: private void addModels(final Key<Model>[] newModels) {
      int before = leaderboard().getModelCount();
      leaderboard().addModels(newModels);
      int after = leaderboard().getModelCount();
      modelCount.addAndGet(after - before);
    }
docs: Also, the leaderboard will reject duplicate models, so use the difference in Leaderboard length here.