How to make 2 tasks run simultaneously in a UWP background app?

I need help running my UWP background app deployed on my Raspberry Pi (hosting Windows 10 IOT Core).

It's almost working but I got a tricky issue... Let me explain:

The app has 2 functionalities:

• A Web Server that receives http requests and do some processing according to parameters. (based on this link)
• A repeating task that is executed every X minutes (X varies from 10 to 60).

Both functionalities work well if executed seperately but I need them to run simultaneously. I'm rather new to UWP & Raspberry so maybe there's something I'm missing...

• Is it a matter of thread conflict?
• Is a background task on a raspberry limited to a single thread (so the first/last process executed wins)?
• Do all classes need to be "sealed" (microsofts's doc says so but not the example they provide)?

I tought about splitting the project into two independant deployable tasks and I believe it would work but I need the webserver task to control (START/PAUSE/STOP) the repeating task.

I think communication between them could be feasable (using this way) but I'm looking for the simplest/fastest solution here.

Here's the stripped down code (the 3 classes are in separate files):

App class:

public sealed class StartupTask : IBackgroundTask
{
    private static BackgroundTaskDeferral _Deferral = null;

    public async void Run(IBackgroundTaskInstance taskInstance)
    {
        _Deferral = taskInstance.GetDeferral();

        var webserver = new WebServer();
        await ThreadPool.RunAsync(workItem => { webserver.Start(); });

        StartRepeatingTask();
    }
}

Web server class:

internal class WebServer
{
    private const uint BUFFER_SIZE = 8192;

    public async void Start()
    {
        var listener = new StreamSocketListener();
        await listener.BindServiceNameAsync("1537");

        listener.ConnectionReceived += async (sender, args) =>
        {
            // Do some stuff
            ...
            Processing.StopProcess();
        }
    }
}

Processing class

public class Processing 
{
    private static Task myTask = null;
    private static CancellationTokenSource taskCancellation = new CancellationTokenSource();

    public static void StartRepeatingTask()
    {
        taskCancellation = new CancellationTokenSource();
        myTask = Task.Run(() => AutoProcess(), taskCancellation.Token);
    }

    public static void AutoProcess()
    {
        Process();

        myTask = Task.Delay(GetDelayToUse(DELAY_SET_LIST))
            .ContinueWith(t => AutoProcess(), taskCancellation.Token);
    }

    public static void Process()
    {
        // Do some other stuff
    }

    public static void StopProcess()
    {
        taskCancellation.Cancel();
    }
}