跨AppDomain调用，使用CreateInstanceFromAndUnwrap创建的对象怎么调用异步方法?

Question

代码如下

static async Task TestAsync()
{
    var appDomain = AppDomain.CreateDomain("ChildApp1");
    ProxyObject obj = (ProxyObject)appDomain.CreateInstanceFromAndUnwrap(currentAsmName, "MainApp.ProxyObject");
    var ret =await obj.FuncAsync();
}


public class ProxyObject : MarshalByRefObject
{
    public async Task<string> FuncAsync()
    {
        return "good";
    }
}

调用TestAsync()时，会报“System.Threading.Tasks.Task”未标记为可序列化
有办法实现么，还是没办法用？