Why is there not an update interface here?

[bodong1987]

https://docs.microsoft.com/en-us/windows/apps/design/shell/tiles-and-notifications/toast-progress-bar?tabs=xml
`using Windows.UI.Notifications;

public void UpdateProgress()
{
// Construct a NotificationData object;
string tag = "weekly-playlist";
string group = "downloads";

// Create NotificationData and make sure the sequence number is incremented
// since last update, or assign 0 for updating regardless of order
var data = new NotificationData
{
    SequenceNumber = 2
};

// Assign new values
// Note that you only need to assign values that changed. In this example
// we don't assign progressStatus since we don't need to change it
data.Values["progressValue"] = "0.7";
data.Values["progressValueString"] = "18/26 songs";

// Update the existing notification's data by using tag/group
ToastNotificationManager.CreateToastNotifier().Update(data, tag, group);

}`

I want to add a progress bar and update the percent value realtime.