docs: def start(self):
          """
          Start the HTTP change monitoring thread.
  
          """
          # Store reference to message queue in module global variable, so that
          # our Bottle app handler functions have easy access to it.
          global _Q_ROUTE_SPEC
          _Q_ROUTE_SPEC = self.q_route_spec
  
          logging.info("Http watcher plugin: "
                       "Starting to watch for route spec on "
                       "'%s:%s/route_spec'..." %
                       (self.conf['addr'], self.conf['port']))