@Override
    public void add(int index, E element) {
      synchronized (mutex) {
        delegate().add(index, element);
      }
    }

    @Override
    public boolean addAll(int index, Collection<? extends E> c) {
      synchronized (mutex) {
        return delegate().addAll(index, c);
      }
    }

    @Override
    public E get(int index) {
      synchronized (mutex) {

    @Override
    public void add(int index, E element) {
      synchronized (mutex) {
        delegate().add(index, element);
      }
    }

    @Override
    public boolean addAll(int index, Collection<? extends E> c) {
      synchronized (mutex) {
        return delegate().addAll(index, c);
      }
    }

    @Override
    public E get(int index) {
      synchronized (mutex) {

  }

  public void testIndexOf() {
    assertThat(Booleans.indexOf(EMPTY, ARRAY_FALSE)).isEqualTo(-1);
    assertThat(Booleans.indexOf(ARRAY_FALSE, ARRAY_FALSE_TRUE)).isEqualTo(-1);
    assertThat(Booleans.indexOf(ARRAY_FALSE_FALSE, ARRAY_FALSE)).isEqualTo(0);
    assertThat(Booleans.indexOf(ARRAY_FALSE, ARRAY_FALSE)).isEqualTo(0);
    assertThat(Booleans.indexOf(ARRAY_FALSE_TRUE, ARRAY_FALSE)).isEqualTo(0);

  public void testIndexOf() {
    assertThat(Shorts.indexOf(EMPTY, (short) 1)).isEqualTo(-1);
    assertThat(Shorts.indexOf(ARRAY1, (short) 2)).isEqualTo(-1);
    assertThat(Shorts.indexOf(ARRAY234, (short) 1)).isEqualTo(-1);
    assertThat(Shorts.indexOf(new short[] {(short) -1}, (short) -1)).isEqualTo(0);
    assertThat(Shorts.indexOf(ARRAY234, (short) 2)).isEqualTo(0);
    assertThat(Shorts.indexOf(ARRAY234, (short) 3)).isEqualTo(1);

        assertThat(ArrayUtil.indexOf(array, "222"), is(1));
        assertThat(ArrayUtil.indexOf(array, "222", 2), is(3));
        assertThat(ArrayUtil.indexOf(array, new Object()), is(-1));
        assertThat(ArrayUtil.indexOf(array, null), is(-1));
        array[1] = null;
        assertThat(ArrayUtil.indexOf(array, null), is(1));
    }

    /**
     * @throws Exception
     */

        String result = original;

        // Unquote
        if (result.indexOf('\"') >= 0) {
            final Matcher m = QUOTE_REPLACE_PATTERN.matcher(original);
            if (m.matches()) {
                result = m.group(1);
            }

            // Unescape
            if (result.indexOf(ESCAPED_QUOTE) >= 0) {
                result = result.replace(ESCAPED_QUOTE, "\"");
            }

    assertThat(iia.indexOf(1)).isEqualTo(0);
    assertThat(iia.indexOf(8)).isEqualTo(5);
    assertThat(iia.indexOf(4)).isEqualTo(-1);
    assertThat(ImmutableDoubleArray.of(13).indexOf(13)).isEqualTo(0);
    assertThat(ImmutableDoubleArray.of().indexOf(21)).isEqualTo(-1);
    assertThat(iia.subArray(1, 5).indexOf(1)).isEqualTo(0);
  }

  public void testIndexOf_specialValues() {

	// divisor, it avoids loops.
	slices.Sort(setCounts)

	return setCounts
}

// getSetIndexes returns list of indexes which provides the set size
// on each index, this function also determines the final set size
// The final set size has the affinity towards choosing smaller
// indexes (total sets)

            final int indexOf = field.indexOf(':');
            if (indexOf < 0) {
                return new Pair<>(field, null);
            }
            final String indexField = indexOf == 0 ? defaultField : field.substring(0, indexOf);
            final String extensionKey = field.substring(indexOf + 1);
            return new Pair<>(indexField, extensionKey);
        }
    }

        list.addLast("1");
        list.addLast("2");
        list.addLast("3");
        assertThat(list.indexOf(null), is(0));
        assertThat(list.indexOf("1"), is(1));
        assertThat(list.indexOf("2"), is(2));
        assertThat(list.indexOf("3"), is(3));
        assertThat(list.indexOf("4"), is(-1));
    }