support openWXApp

lib/src/fluwx_iml.dart

@@ -311,6 +311,8 @@ Future subscribeMsg({
   );
 }
 
+
+/// please read official docs.
 Future autoDeDuct({
   @required String appId,
   @required String mchId,
@@ -341,6 +343,10 @@ Future autoDeDuct({
   });
 }
 
+Future<bool> openWeChatApp() async{
+  return await _channel.invokeMethod("openWXApp");
+}
+
 _handleOnAuthByQRCodeFinished(MethodCall methodCall) {
   int errCode = methodCall.arguments["errCode"];
   _authByQRCodeFinishedController.add(AuthByQRCodeResult(