@PostConstruct
	public void init() {
		// blockRequestHandlerOptional has low priority
		blockRequestHandlerOptional.ifPresent(GatewayCallbackManager::setBlockHandler);
		initAppType();
		initFallback();
	}
@Test
	public void testInitWithFallbackRedirect() {
		FallbackProperties fallbackProperties = mock(FallbackProperties.class);
		when(gatewayProperties.getFallback()).thenReturn(fallbackProperties);
		when(fallbackProperties.getMode()).thenReturn(ConfigConstants.FALLBACK_REDIRECT);
		when(fallbackProperties.getRedirect()).thenReturn("/test");
		config.init();
		Mono<ServerResponse> responseMono = GatewayCallbackManager.getBlockHandler()
				.handleRequest(mock(ServerWebExchange.class), null);
		HttpHeaders headers = Objects.requireNonNull(responseMono.block()).headers();
		List<String> location = headers.get("Location");
		Assert.assertNotNull(location);
		Assert.assertEquals("/test", location.get(0));
	}