using System;

using System.Threading.Tasks;

public class Program

{

    public static void Main()

    {

        (new Program()).MainAsync().Wait();

    }

    public async Task MainAsync()

    {

        var requestTask = Task.Factory.StartNew<object>(() => 

                                              {

                                                  throw new Exception("This is the base exception");

                                              });

        var responseHandlerTask = requestTask.ContinueWith(t => Callback(t));

        var responseContent = await responseHandlerTask;

    }

​

    public object Callback(Task<object> task)

    {

        return task.Result;

    }   

}