* @param listener Listener instance which is being registered
* @return A {@link Registration} object, which may be used to unregister your listener using
* {@link Registration#close()} to stop delivery of change events.
* @param listener Listener instance which is being registered
* @return A {@link Registration} object, which may be used to unregister your listener using
* {@link Registration#close()} to stop delivery of change events.