ViewModel.cs

class ViewModel
{
    public ReactiveProperty<string> Input { get; }
    public ReactiveProperty<string> Output { get; }

    public ViewModel()
    {
        Input = new ReactiveProperty("");
        Output = Input
            .Delay(TimeSpan.FromSecond(1)) // Using a Rx method.
            .Select(x => x.ToUpper()) // Using a LINQ method.
            .ToReactiveProperty(); // Convert to ReactiveProperty
    }
}