public static IRouterBuilder Default <TViewModel>(this IRouterBuilder builder, object parameters) =>
 builder.Default(route => route.SetViewModel(typeof(TViewModel)), parameters);
 public static IRouterBuilder Default <TViewModel>(this IRouterBuilder builder) where TViewModel : IActivatable <Unit> =>
 builder.Default(route => route.SetViewModel(typeof(TViewModel)), Unit.Default);
        public void Test_Default_Returns_RouteBuilder()
        {
            var returned = builder.Default(route => route, Unit.Default);

            returned.Should().Be(builder);
        }