Cancel/Abort a Closing Window in Xamarin.Mac

Close Dialog

I began by researching the WillClose event to accomplish this. With it I could detect the window as it was closing but could not find a way to abort with the EventArgs provided. I achieved success with a delegate class that overrides the WindowShouldClose method .
Put this class in the window.cs below the partial class that was pregenerated:

Assign the delegate wherever you instantiate the window controller: