@Test
public void testAttachInvocationIdIfAsync_normal() {
URL url = URL.valueOf("dubbo://localhost/?test.async=true");
Map<String,String> attachments = new HashMap<String,String>();
attachments.put("aa", "bb");
Invocation inv = new RpcInvocation("test", new Class[]{}, new String[]{}, attachments);
RpcUtils.attachInvocationIdIfAsync(url, inv);
long id1 = RpcUtils.getInvocationId(inv);
RpcUtils.attachInvocationIdIfAsync(url, inv);
long id2 = RpcUtils.getInvocationId(inv);
Assert.assertTrue( id1 == id2); //幂等操作验证