C#: What are background services in ASP.NET Core?

1public class OrderProcessingService : BackgroundService
2{
3    private readonly IServiceScopeFactory _scopeFactory;
4    private readonly ILogger<OrderProcessingService> _logger;
5
6    public OrderProcessingService(
7        IServiceScopeFactory scopeFactory,
8        ILogger<OrderProcessingService> logger)
9    {
10        _scopeFactory = scopeFactory;
11        _logger = logger;
12    }
13
14    protected override async Task ExecuteAsync(
15        CancellationToken stoppingToken)
16    {
17        while (!stoppingToken.IsCancellationRequested)
18        {
19            using var scope = _scopeFactory.CreateScope();
20            var orderService = scope.ServiceProvider
21                .GetRequiredService<IOrderService>();
22
23            await orderService.ProcessPendingOrdersAsync();
24            await Task.Delay(TimeSpan.FromSeconds(30), stoppingToken);
25        }
26    }
27}

1builder.Services.AddHostedService<OrderProcessingService>();

1public class MyService : IHostedService
2{
3    public Task StartAsync(CancellationToken ct) => Task.CompletedTask;
4    public Task StopAsync(CancellationToken ct) => Task.CompletedTask;
5}