This project started as a prototype of an official Vaadin Spring add-on, back in the day when Vaadin 8 was new. That was many years ago and a lot has happened since that time. Now we have Vaadin 14 and I have deleted almost all of the extensions and addons since it did not make sense to port them to Vaadin 14.
All that remains is the event bus that is kept by popular demand. Please note, however, that the event bus has a design flaw that can lead to potentially serious security problems if used in the wrong way. Check the README for more information.