flutter右滑返回直接返回到native问题

iOS跳flutterViewController后，flutter1又跳了flutter2，flutter2侧滑返回总是返回到原生，期望侧滑返回到flutter1页面。

解决方案：

在iOS原生导航类 BaseNavigationController 中，修改下面代理方法，如果是flutter类，就禁用了iOS原生手势。这样flutter的侧滑手势优先级就上来了。

 - (void)navigationController:(UINavigationController *)navigationController didShowViewController:(UIViewController *)viewController animated:(BOOL)animated{
    if ([viewController isKindOfClass:[FlutterViewController class]]) {
        self.interactivePopGestureRecognizer.enabled = NO;
    } else {
        self.interactivePopGestureRecognizer.enabled = YES;
    }
}