@Override
  public @NotNull ModificationTracker forLanguage(@NotNull Language language) {
    SimpleModificationTracker languageTracker = myLanguageTrackers.get(language);
    return () -> languageTracker.getModificationCount() +
                 myAllLanguagesTracker.getModificationCount();
  }
@Override
  public @NotNull ModificationTracker forLanguage(@NotNull Language language)