using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine((GetStuff1()

            ?.MultiplyBy(2.0f))

            .DoThing(42));

        Console.WriteLine((GetStuff2()

            ?.MultiplyBy(2.0f))

            .DoThing(42));

    }

    private static int? GetStuff1()

    {

        return 5;

    }

    private static int? GetStuff2()

    {

        return null;

    }

}

​

public static class Extender

{

    public static float MultiplyBy(this int b, float factor)

    {

        return b * factor;

    }

    public static float? DoThing(this float? x, float y)

    {

        if (x == null) return null;

        else return y;

    }

}