public Builder add(long value) {
      ensureRoomFor(1);
      array[count] = value;
      count += 1;
      return this;
    }

    /**
     * Appends {@code values}, in order, to the end of the values the built {@link
     * ImmutableLongArray} will contain.
     */
    @CanIgnoreReturnValue
    public Builder addAll(long[] values) {
      ensureRoomFor(values.length);

    public Builder add(int value) {
      ensureRoomFor(1);
      array[count] = value;
      count += 1;
      return this;
    }

    /**
     * Appends {@code values}, in order, to the end of the values the built {@link
     * ImmutableIntArray} will contain.
     */
    @CanIgnoreReturnValue
    public Builder addAll(int[] values) {
      ensureRoomFor(values.length);

     * elements without being resized. Also, if we've already built a collection backed by the
     * current array, create a new array.
     */
    private void ensureRoomFor(int newElements) {
      @Nullable Object[] contents = this.contents;
      int newCapacity = expandedCapacity(contents.length, size + newElements);
      // expandedCapacity handles the overflow case