docs: def LogHttpFrontendAccess(self, request, source=None, message_count=None):
      """Write a log entry for a Frontend or UI Request.
  
      Args:
        request: A HttpRequest protobuf.
        source: Client id of the client initiating the request. Optional.
        message_count: Number of messages received from the client. Optional.
      """
      # TODO(user): generate event_id elsewhere and use it for all the log
      # messages that have to do with handling corresponding request.
      event_id = self.GetNewEventId()
  
      log_msg = "%s-%s [%s]: %s %s %s %s (%d)" % (
          event_id, request.source_ip, source or "<unknown>", request.method,
          request.url, request.user_agent, request.user, message_count or 0)
      logging.info(log_msg)