@Override
    public ImmutableMap<K, V> updated(K key, V value) {
        return new PCollectionsImmutableMap<>(underlying().plus(key, value));
    }
@Test
    public void testDelegationOfUpdated() {
        new PCollectionsHashMapWrapperDelegationChecker<>()
            .defineMockConfigurationForFunctionInvocation(mock -> mock.plus(eq(this), eq(this)), SINGLETON_MAP)
            .defineWrapperFunctionInvocationAndMockReturnValueTransformation(wrapper -> wrapper.updated(this, this), identity())
            .expectWrapperToWrapMockFunctionReturnValue()
            .doFunctionDelegationCheck();
    }