Rework the demo

Doing this quick commit to test that in my Mac

examples/simple_room/src/events.rs

@@ -0,0 +1,9 @@
+#[derive(Debug)]
+pub enum AsyncCmd {
+    RoomConnect { url: String, token: String },
+}
+
+#[derive(Debug)]
+pub enum UiCmd {
+    ConnectResult,
+}