@Test
    @ClearSystemProperty(key = "com.linecorp.armeria.transientServiceOptions")
    void defaultTransientServiceOptions() throws Throwable {
        assertFlags("transientServiceOptions").isEqualTo(ImmutableSet.of());
    }
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