public DataRangeViewModel()
 {
     Output = From.CombineLatest(To, (a, b) => new { a, b })
              .Where(g => g.a < g.b)
              .Select(_ => new UtilityModel.Range <DateTime> {
         Minimum = _.a, Maximum = _.b
     })
              .Throttle(TimeSpan.FromSeconds(1))
              .ToReactiveProperty();
 }