private static void shutdown() {
        if (!ALREADY_SHUTDOWN.compareAndSet(false, true)) {
            return;
        }
        LOGGER.warn("[HttpClientBeanHolder] Start destroying common HttpClient");
        
        try {
            shutdown(DefaultHttpClientFactory.class.getName());
        } catch (Exception ex) {
            LOGGER.error("An exception occurred when the common HTTP client was closed : {}",
                    ExceptionUtil.getStackTrace(ex));
        }
        
        LOGGER.warn("[HttpClientBeanHolder] Destruction of the end");
    }
@Test
    void shutdown() throws Exception {
        HttpClientBeanHolder.getNacosRestTemplate((Logger) null);
        HttpClientBeanHolder.getNacosAsyncRestTemplate((Logger) null);
        assertEquals(1, restMap.size());
        assertEquals(1, restAsyncMap.size());
        HttpClientBeanHolder.shutdown(DefaultHttpClientFactory.class.getName());
        assertEquals(0, restMap.size());
        assertEquals(0, restAsyncMap.size());
    }