HostingEnvironment.QueueBackgroundWorkItem

HomeController.cs

using System;
using System.Diagnostics;
using System.Threading;
using System.Threading.Tasks;
using System.Web.Hosting;
using System.Web.Mvc;

namespace QueueBackgroundWorkItem.Controllers
{
    public class HomeController : Controller
    {
        // notice that the action did need to be declared async
        public ActionResult Index()
        {
            Func<CancellationToken, Task> workItem = DelayWrite;

            HostingEnvironment.QueueBackgroundWorkItem(workItem);

            // the view is returned before the work item is complete
            return View();
        }

        // Background work items should use async/await to avoid tying up IIS threads
        // the runtime will provide the cancellation token
        private async Task DelayWrite(CancellationToken cancellationToken)
        {
            // perform a long running operation, e.g. network service call, computation, file IO
            await Task.Delay(5000);
            Trace.WriteLine("Executed from a background work item");         
        } 

    }
}