@Test
    @ClearSystemProperty(key = "com.linecorp.armeria.defaultPreferHttp1")
    void defaultValueOfDefaultUseHttp1Preface() throws Throwable {
        assertFlags("defaultPreferHttp1").isEqualTo(false);
    }
Makes sure OpenSSL SSLEngine is used instead of JDK SSLEngine while running tests
on Linux, Windows and OS X.
core/src/test/java/com/linecorp/armeria/common/FlagsTest.java