CancellationTokenExample.cs

namespace ConsoleApp7
{
    using System.Threading;
    using System.Threading.Tasks;
    using Autofac;
    using Autofac.Extensions.DependencyInjection;
    using Microsoft.Extensions.Hosting;
    using Rebus.Bus;
    using Rebus.Config;

    public class Message
    {

    }

    public class WindowsService : IHostedService
    {
        private readonly IBus _bus;
        private readonly CancellationTokenSource _cancellationTokenSource;

        public WindowsService(IBus bus, CancellationTokenSource cancellationTokenSource)
        {
            _bus = bus;
            _cancellationTokenSource = cancellationTokenSource;
        }

        public async Task StartAsync(CancellationToken cancellationToken)
        {
            await _bus.Subscribe<Message>();
        }

        public Task StopAsync(CancellationToken cancellationToken)
        {
            _cancellationTokenSource.Cancel(); // This will set internal rebus token to cancelled
            return Task.CompletedTask;
        }

    }

    class Program
    {
        static async Task Main(string[] args)
        {
            var cancellationTokenSource = new CancellationTokenSource();
            var hostBuilder = new HostBuilder()
                .UseServiceProviderFactory(new AutofacServiceProviderFactory())
                .ConfigureContainer<ContainerBuilder>((context, builder) =>
                {
                    builder.RegisterInstance(cancellationTokenSource).AsSelf();

                    builder
                        .RegisterRebus((configurer, c) => configurer.Transport(t => t.UseRabbitMq("connString", "inputQueue")));
                    /**
                     * Ideally here do something like
                     * RegisterCancellationTokenSource(cancellationTokenSource)
                    */
                });

            await hostBuilder.RunConsoleAsync(cancellationTokenSource.Token);

        }
    }
}