@Test
public void test_getAdaptiveExtension_protocolKey() throws Exception {
UseProtocolKeyExt ext = ExtensionLoader.getExtensionLoader(UseProtocolKeyExt.class).getAdaptiveExtension();
{
String echo = ext.echo(URL.valueOf("1.2.3.4:20880"), "s");
assertEquals("Ext3Impl1-echo", echo); // 缺省值
Map<String, String> map = new HashMap<String, String>();
URL url = new URL("impl3", "1.2.3.4", 1010, "path1", map);