Notification Essential

A notification to the user containing a message and type.

Event Subscription

Invoke the given callback when the notification is dismissed.

Argument	Description
`callback`	Function to be called when the notification is dismissed.

Return values
Returns a Disposable on which `.dispose()` can be called to unsubscribe.

Invoke the given callback when the notification is displayed.

Argument	Description
`callback`	Function to be called when the notification is displayed.

Return values
Returns a Disposable on which `.dispose()` can be called to unsubscribe.

Return values
Returns the String type.

Return values
Returns the String message.

Dismisses the notification, removing it from the UI. Calling this programmatically will call all callbacks added via onDidDismiss.