How do I call an asynchronous process from an hosted module using C#5 async / await?

I have a long running process that is called via a Nancy Module Get method. Rather than have the browser hang while the process runs I would like this call to be asynchronous, in other words I want the Get method to return right away and leave the long running process to do its thing. I could then check the status of the process at regular intervals and act accordingly.