A notification manager used to create Notifications to be shown
to the user.
Invoke the given callback after a notification has been added.
Function to be called after the notification is added.
The Notification that was added.
Returns a Disposable on which .dispose() can be called to unsubscribe.
Add a success notification.
A String message
An options Object with optional keys such as:
A String with additional details about the notification
Add an informational notification.
Add a warning notification.
Add an error notification.
Add a fatal error notification.
Get all the notifications.
Returns an Array of Notificationss.