Listener for topic notifications.
Called when the listener is closed. The listener will be closed if the session is closed, or if the listener is closed by the TopicNotificationRegistration
Once closed, no further calls will be made to the listener.
Notification for an immediate descendant of a selected topic path. This notifies the presence or absence of a descendant topic that may subsequently be explicitly selected.
the path of the selected immediate descendant
the type of notification
Notification of a contextual error related to this listener. This is
analogous to an Error being thrown. Situations in which
onError is called include the session being closed before the
listener is registered, a communication timeout, or a problem with the
provided parameters. No further calls will be made to this listener.