MyStartup.cs

namespace Notifications
{
    public partial class MyStartup : ShinyStartup
    {
        ...
        
        public override void ConfigureServices(IServiceCollection services, IPlatform platform)
        {
            // Adicionamos o uso das notificacoes
            services.UseNotifications();
            services.UseFirebaseMessaging<PushDelegate>();
        }

        ...
    }
}