Had a look at the link and struggling to understand the concept of streams. A primary benefit of sync is store-and-forward, i.e. I could be offline, change a c

Had a look at the link and struggling to understand the concept of streams. A primary benefit of sync is store-and-forward, i.e. I could be offline, change a customer record, and when I reconnect it syncs to those who need it via a server. In the streams model, how does the server know which stream messages to send to a client that's been offline for a week, if not via sync? Also, messages. Does a message equate to, say, a customer record? I read that a message is a record of an event that happened to something?