public void test_getAdaptiveExtension_protocolKey() throws Exception {
Ext3 ext = ExtensionLoader.getExtensionLoader(Ext3.class).getAdaptiveExtension();
Config config = Config.fromKv("protocol", "impl3", "host", "1.2.3.4", "port", "1010", "path", "path1");
String echo = ext.echo(config, "s");
assertEquals("Ext3Impl3-echo", echo);
config = config.addConfig("key1", "impl2");
echo = ext.echo(config, "s");
assertEquals("Ext3Impl2-echo", echo);