Quote from Tomasz on https://github.com/wildfly/wildfly-discovery/pull/29 :

I'm adding this API to be able to implement algorithms not based on polling. I think it is necessary for HTTP based discovery - one of the reasons would be that HTTP-over-EJB is cluster agnostic by design. Furthermore, this API maybe useful to provide alternative discovery algorithms.

Furthermore, this is needed for the upgrading of jbos-ejb-client to 4.0.36.Final to use the new API.