@Override
    public void update(V newValue) {
        throw MODIFICATION_ATTEMPT_ERROR;
    }
@Test
    void testUpdate() throws IOException {
        long value = valueState.value();
        assertThat(value).isEqualTo(42L);
        assertThatThrownBy(() -> valueState.update(54L))
                .isInstanceOf(UnsupportedOperationException.class);
    }