O r</p><div class="doc"><p>Create a publisher with the lifetime of the scope
   of the user action passed in.
   The publisher, internally, creates a registry
   to which subscribers will connect to obtain the topic data.
   The registry will not expect heartbeats from subscribers,
   since the dependability relation is the other way round:
   the publisher does not depend on subscribers,
   but subscribers depend on a publisher.
   The publisher, usually, does not send heartbeats either.
   For exceptions 