docs: def unsubscribe(self, frame):
          """
          Handle the UNSUBSCRIBE command: Removes this connection from destination.
          """
          dest = frame.headers.get('destination')
          if not dest:
              raise ProtocolError('Missing destination for UNSUBSCRIBE command.')
  
          if dest.startswith('/queue/'):
              self.engine.queue_manager.unsubscribe(self.engine.connection, dest)
          else:
              self.engine.topic_manager.unsubscribe(self.engine.connection, dest)