SqlDependency creates 3 Processes

I'm using sqlDependency library for database notification. But when I opened Activity Monitor I saw that there are 3 Processes in suspend status. I stoped application they all gone. I started again and they all came back.

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Can someone explain me why it happened.

this is my Global asax. I start sqldependency just here.

    protected void Application_Start()
    {
        EntityConnectionStringBuilder entityConnectionStringBuilder = new EntityConnectionStringBuilder(_connectionString);
        AreaRegistration.RegisterAllAreas();
        RouteConfig.RegisterRoutes(RouteTable.Routes);
        BundleConfig.RegisterBundles(BundleTable.Bundles);

        log4net.Config.XmlConfigurator.Configure();
        SqlDependency.Start(entityConnectionStringBuilder.ProviderConnectionString);
    }

    protected void Application_End()
    {
        EntityConnectionStringBuilder entityConnectionStringBuilder = new EntityConnectionStringBuilder(_connectionString);
        //Stop SQL dependency
        SqlDependency.Stop(entityConnectionStringBuilder.ProviderConnectionString);
    }