@Nullable
        static <T, A> SideEffect<T> fixedFrom(ExecutionTimeValue<A> value) {
            if (!value.hasFixedValue()) {
                return null;
            }

            return fixed(value.getFixedValue(), value.getSideEffect());
        }

        /**
         * Creates a new side effect that executes given side effects sequentially.
         */
        @Nullable

        expect:
        assertHasKnownProducer(property)
        def value = property.calculateExecutionTimeValue()
        value.hasFixedValue()
        !value.hasChangingContent()
        value.getFixedValue().isEmpty()
    }

    def "has no producer and missing execution time value when element provider with no value added"() {
        given:
        property.putAll([a: '1', b: '2'])

        property.set(someValue())
        property.finalizeValueOnRead()

        expect:
        property.calculateExecutionTimeValue().getFixedValue() == someValue()
        property.set(someOtherValue())
        property.calculateExecutionTimeValue().getFixedValue() == someOtherValue()
        property.get() == someOtherValue()
    }

        if (value.isMissing()) {
            setSupplier(noValueSupplier());
        } else if (value.hasFixedValue()) {
            setSupplier(new FixedSupplier<>(value.getFixedValue(), Cast.uncheckedCast(value.getSideEffect())));
        } else {
            CollectingProvider<T, C> asCollectingProvider = Cast.uncheckedNonnullCast(value.getChangingValue());

        if (value.isMissing()) {
            setSupplier(noValueSupplier());
        } else if (value.hasFixedValue()) {
            setSupplier(new FixedSupplier<>(uncheckedNonnullCast(value.getFixedValue()), uncheckedCast(value.getSideEffect())));
        } else {
            CollectingProvider<K, V> asCollectingProvider = uncheckedNonnullCast(value.getChangingValue());

        expect:
        assertHasKnownProducer(property)
        def value = property.calculateExecutionTimeValue()
        value.hasFixedValue()
        !value.hasChangingContent()
        value.getFixedValue().isEmpty()
    }

    def "has no producer and missing execution time value when element provider with no value added"() {
        given:
        property.addAll("a", "b")