* PubSub is a protocol which fasten up RSS fetching:
* - Every time a new link is posted, Shaarli notify the hub.
* - The hub notify all feed subscribers that a new link has been posted.
* PubSub is a protocol which fasten up RSS fetching:
* - Every time a new link is posted, Shaarli notify the hub.
* - The hub notify all feed subscribers that a new link has been posted.