What is a good way to create an IObservable for a method?

Question

Let\'s say, we have a class:

public class Foo
{
   public string Do(int param)
   {
   }
}

I\'d like to create an observable of values that are

Answer 1

Matt's answer made me thinking about this:

public class Foo
{
    private readonly Subject _doValues = new Subject();

    public IObservable DoValues { get { return _doValues; } }

    public string Do(int param)
    {
        var ret = (param * 2).ToString();
        _doValues.OnNext(ret);
        return ret;
    }
}


var foo = new Foo();
foo.DoValues.Subscribe(Console.WriteLine);
foo.Do(2);