queue_dir            (path)               staging dir for undelivered messages e.g. '/home/events'
queue_limit          (number)             maximum limit for undelivered messages, defaults to '100000'
max_open_connections (number)             maximum number of open connections to the database, defaults to '2'
comment              (sentence)           optionally add a comment to this setting
```

or environment variables

```

			Table:              env.Get(tableEnv, kv.Get(target.MySQLTable)),
			QueueDir:           env.Get(queueDirEnv, kv.Get(target.MySQLQueueDir)),
			QueueLimit:         queueLimit,
			MaxOpenConnections: maxOpenConnections,
		}
		if err = mysqlArgs.Validate(); err != nil {
			return nil, err
		}
		mysqlTargets[k] = mysqlArgs
	}
	return mysqlTargets, nil
}