def logging_api(self):
        """Helper for logging-related API calls.

        See
        https://cloud.google.com/logging/docs/reference/v2/rest/v2/entries
        https://cloud.google.com/logging/docs/reference/v2/rest/v2/projects.logs
        """
        if self._logging_api is None:
            if self._use_grpc:
                self._logging_api = _gapic.make_logging_api(self)
            else:
                self._logging_api = JSONLoggingAPI(self)
        return self._logging_api