Writes a log message to the logger destination.

        :param level: a log level.

        :param correlation_id: (optional) transaction id to trace execution through call chain.

        :param error: an error object associated with this message.

        :param message: a human-readable message to log.

def _write(self, level, correlation_id, error, message):
        """
        Writes a log message to the logger destination.

        :param level: a log level.

        :param correlation_id: (optional) transaction id to trace execution through call chain.

        :param error: an error object associated with this message.

        :param message: a human-readable message to log.
        """
        for logger in self._loggers:
            logger.log(level, correlation_id, error, message)