bg-worker.cs

/// <summary>
/// Native Background Worker Interface
/// </summary>
public interface IBackgroundWorker
{
    /// <summary>
    /// Worker Stopped Event
    /// </summary>
    public event EventHandler WorkerStopped;

    /// <summary>
    /// Actual Background Work
    /// </summary>
    public Func<Task> BackgroundWork { get; }

    /// <summary>
    /// Start Native Background or Foreground Service
    /// </summary>
    void StartWorker(Func<Task> backgroundWork);
    
    /// <summary>
    /// Force stop worked foreground or background service
    /// </summary>
    void StopWorker();
}

/// <summary>
/// Native Background Worker
/// </summary>
public class BackgroundWorker : IBackgroundWorker
{
    /// <summary>
    /// Worker Stopped Event
    /// </summary>
    public event EventHandler WorkerStopped;
    
    /// <summary>
    /// Actual Background Work
    /// </summary>
    public Func<Task> BackgroundWork { get; private set; }
    
    #region Public Methods

    /// <summary>
    /// Start Native Background or Foreground Service
    /// </summary>
    public void StartWorker(Func<Task> backgroundWork)
    {
        BackgroundWork = backgroundWork;
        var intent = new Intent(Application.Context, typeof(BackgroundService));

        if (Build.VERSION.SdkInt >= BuildVersionCodes.O)
        {
            Application.Context.StartForegroundService(intent);
        }
        else
        {
            Application.Context.StartService(intent);
        }
    }

    /// <summary>
    /// Force stop worked foreground or background service
    /// </summary>
    public void StopWorker()
    {
        WorkerStopped?.Invoke(this, EventArgs.Empty);
    }

    #endregion Public Methods
}