If the 10 records are related to 10 different items (as I suppose you mean), then Lightstreamer Server will try to send each one as soon as it is generated; hence, ideally, each one in its own TCP packet.
However, as any resource or configuration limitation causes the processing of one update to be delayed until the next one is generated, the Server will collect multiple updates in the same TCP packet.

For instance, bandwidth and frequency constraints may cause update delivery to be delayed.
Moreover, by the default Server configuration, the <max_delay_millis> element setting may cause update delivery to be slightly delayed for the express purpose of minimizing the number of distinct TCP packets to be sent (see the comment note on the configuration file).