code: public static ImmutableIntArray copyOf(Iterable<Integer> values) {
      if (values instanceof Collection) {
        return copyOf((Collection<Integer>) values);
      }
      return builder().addAll(values).build();
    }
docs: Returns an immutable array containing the given values, in order.
  
  <p><b>Performance note:</b> this method delegates to {@link #copyOf(Collection)} if {@code
  values} is a {@link Collection}. Otherwise it creates a {@link #builder} and uses {@link
  Builder#addAll(Iterable)}, with all the performance implications associated with that.