PublisherListener is an abstract class defining the callbacks that will be triggered
in response to state changes on the Publisher.
By default, all these callbacks are empty and do nothing.
The user should implement a specialization of this class overriding the callbacks
that are needed on the application.
Callbacks that are not overridden will maintain their empty implementation.
PublisherListener inherits from DataWriterListener.
Therefore, it has the ability to react to all events that are reported to the
Since events are always notified to the most specific Entity Listener that can handle the event,
PublisherListener inherits from DataWriterListener
will only be called if the triggering DataWriter has
no Listener attached,
or if the callback is disabled by the
StatusMask on the DataWriter.