code: def _log_prefix(self, prefix, request):
          
          # After a celery task runs, the request cache is cleared. So if celery
          # tasks are running synchronously (CELERY_ALWAYS _EAGER), "guid_key"
          # will no longer be in the request cache when process_response executes.
          cached_guid_response = self._cache.get_cached_response(self.guid_key)
          cached_guid = cached_guid_response.get_value_or_default(u"without_guid")
          return u"{} request '{} {} {}'".format(prefix, request.method, request.path, cached_guid)
docs: Returns a formatted prefix for logging for the given request.