ServiceWorker suggestions

[carsten-riedel]

Hi,

nearly did the same, than found your project, nice work !!!

Regarding your Service Worker some suggestion, maybe it makes sense to use a BackgroundService ExecuteAsync and await for appLifetime.ApplicationStarted.
I don't like the fixed _hostLifetime.StopApplication(); either. I should be open who decides to quite the application, it could be done on a command level with _hostLifetime.StopApplication();
Maybe even individual configuration of the worker could be passed via UseSpectreConsole + Action< SpectreServiceWorkerConfig >

 public Task StartAsync(CancellationToken cancellationToken)
    {
        return Task.Factory.StartNew(async () =>
        {
            try
            {
                var args = GetArgs();
                await Task.Delay(100, cancellationToken); //Just to let Microsoft.Hosting finish.
                _exitCode = await _commandApp.RunAsync(args);
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "An unexpected error occurred");
                _exitCode = 1;
            }
            finally
            {
                _hostLifetime.StopApplication();
            }
        }, cancellationToken);
    }