
Explanation

Box 1: NotificationHubClient
Box 2: NotificationHubClient
Box 3: CreateClientFromConnectionString
// Initialize the Notification Hub
NotificationHubClient hub = NotificationHubClient.CreateClientFromConnectionString(listenConnString, hubName); Box 4: SendWindowsNativeNotificationAsync Send the push notification.
var result = await hub.SendWindowsNativeNotificationAsync(windowsToastPayload); Reference:
https://docs.microsoft.com/en-us/azure/notification-hubs/notification-hubs-push-notification-registration-manage
https://github.com/MicrosoftDocs/azure-docs/blob/master/articles/app-service-mobile/app-service-mobile-windo