@Contract(value = "_ -> new", pure = true)
  public static @NotNull <T> ConcurrentList<T> createConcurrentList(@NotNull Collection <? extends T> c) {
    return new LockFreeCopyOnWriteArrayList<>(c);
  }
@Contract(value = "_ -> new", pure = true)
  public static @NotNull <T> ConcurrentList<T> createConcurrentList(@NotNull Collection <? extends T> c)