When no more clients are still subscribing for an item Lightstreamer server send a unsubscribe call for that item to the appropriate Data Adapter; since then no updates for that item will be expected.

In fact, the Data Adapter should not interact with the server as if it were a bus, sending data as a continuous flow, but must interact with the server in response to subscribe and unsubscribe requests.
When a Data Adapter receives a subscribe request it starts to send possibly snapshots and then all the updates, when it receives an unsubscribe request it must stops sending updates, and be ready to repeat the cycle when a new subscribe request arrives.