writehaltchunk <stream_time> <subscriber_id>
Writehaltchunk writes a HALT control chunk to the output stream. The result is a halt chunk keyed to a specified subscriber for a given stream time. The chunk sent to the subscriber at halt time has the subtype HALT. It prevents the streamer thread from delivering data to any subscriber until a reply is received from the specified subscriber.
This essentially provides the specified subscriber with time to process its data while no other data are arriving from the streamer thread.