How to handle unobserved exceptions in asp.net mvc

Question

I am specifically asking about how to handle unobserved exceptions, not unhandled exceptions. This question is also different from this question which is asking about how to raise fire-and-forget async methods, not about how to handle unobserved exceptions, though they are related.

Unobserved exceptions are the type that are caused by the example shown below, taken from here:

Task op1 = FooAsync(); 
Task op2 = BarAsync(); 
await op1; 
await op2;

As a rule I try to avoid this situation, but if it should occur I don't want my web site to exit unexpectedly and I don't want these exceptions to be swallowed silently. I at least want to handle them in one place and log them. I don't want to use elmah.

Now, I think that we can do something like this example from here:

TaskScheduler.UnobservedTaskException += (sender, e) => 
{ 
    Console.WriteLine("Saving the day! This exception would have been unobserved: {0}", 
                      e.Exception); 
    e.SetObserved(); 
};

But, my questions are: -

• Where to put this, can it go in Application_Start()?
• Will these unobserved exceptions make their way into Application_Error()? If so, how do you identity them or prevent them from turning up in Application_Error.

This question is similar, but there is no satisfactory answer / explanation.