when:
        async {
            threadCount.times { i ->
                start {
                    SystemProperties.instance.withSystemProperty(id, "bar", {"baz"})
                }
                start {
                    SystemProperties.instance.withSystemProperties {
                        System.properties.each {
                            assert it.key != id
                        }

        return setSystemProperties(toMap(systemProperties));
    }

    /**
     * Sets the system properties to use for interpolation and profile activation. The system properties are collected
     * from the runtime environment like {@link System#getProperties()} and environment variables.
     *
     * @param systemProperties The system properties, may be {@code null}.

    }

    def "can set system properties"() {
        when:
        options.systemProperties = [key: 12, key2: "value", key3: null]

        then:
        options.systemProperties == [key: 12, key2: "value", key3: null]
    }

    def "can add system properties"() {
        when:
        options.systemProperties(key: 12)
        options.systemProperty('key2', 'value2')

        then:

            this.inactiveProfileIds = inactiveProfileIds;
            return this;
        }

        public ModelBuilderRequestBuilder systemProperties(Map<String, String> systemProperties) {
            this.systemProperties = systemProperties;
            return this;
        }

        public ModelBuilderRequestBuilder userProperties(Map<String, String> userProperties) {

        config.daemonMemory = this.daemonMemory
        config.compilerMemory = this.compilerMemory
        config.testRunnerMemory = '256m'
        config.parallel = this.subProjects > 0
        config.systemProperties = this.systemProperties
        config.featurePreviews = this.featurePreviews

        config.maxWorkers = 4
        config.maxParallelForks = this.subProjects > 0 ? 1 : 4
        config.testForkEvery = 1000

            this.description = "Runs the cross-version tests against Gradle ${targetVersion.version}"
            this.systemProperties["org.gradle.integtest.versions"] = targetVersion.version
            this.systemProperties["org.gradle.integtest.crossVersion"] = "true"
            this.systemProperties["org.gradle.integtest.crossVersion.lowestTestedVersion"] = releasedVersions.lowestTestedVersion.version
            this.useJUnitPlatform {

            Map<String, String> systemProperties = new HashMap<String, String>();
            for (Map.Entry<Object, Object> entry : System.getProperties().entrySet()) {
                systemProperties.put(entry.getKey().toString(), entry.getValue() == null ? null : entry.getValue().toString());
            }

    }

    public BuildLayoutResult convert(InitialProperties systemProperties, ParsedCommandLine commandLine, @Nullable File workingDir) {
        return convert(systemProperties, commandLine, workingDir, parameters -> {
        });
    }

    public BuildLayoutResult convert(InitialProperties systemProperties, ParsedCommandLine commandLine, @Nullable File workingDir, Consumer<BuildLayoutParameters> defaults) {

        }
    }

    private class AsyncDownload implements IDownload {
        private final Map<String, String> systemProperties;

        public AsyncDownload(Map<String, String> systemProperties) {
            this.systemProperties = systemProperties;
        }

        @Override
        public void download(URI address, File destination) throws Exception {
            synchronized (lock) {

                .replaceAll(SystemProperties.getInstance().getLineSeparator(), "\\\\" + SystemProperties.getInstance().getLineSeparator())
                .replace("\'", "\\'"));
        write("\'");
        return this;
    }