How to call an async method and get a result back without using dynamics

How to call an async method and get a result back without using dynamics

I want to call an async method with reflection. As I figured out there are two ways to do that

await (Task) objType.GetTypeInfo()
                    .GetDeclaredMethod("ThePrivateMethod")
                    .Invoke(theObject, null);

or

await (dynamic) objType.GetTypeInfo()
                       .GetDeclaredMethod("ThePrivateMethod")
                       .Invoke(theObject, null);

The Problem is if I don’t know the return type I need to do it like in the second example. But my problem is I can't use dynamics in my project. How can I call an async Method without knowing the return type and not using dynamics.