MINIO_NOTIFY_MQTT_KEEP_ALIVE_INTERVAL  (duration)  keep-alive interval for MQTT connections in s,m,h,d
MINIO_NOTIFY_MQTT_RECONNECT_INTERVAL   (duration)  reconnect interval for MQTT connections in s,m,h,d
MINIO_NOTIFY_MQTT_QUEUE_DIR            (path)      staging dir for undelivered messages e.g. '/home/events'
MINIO_NOTIFY_MQTT_QUEUE_LIMIT          (number)    maximum limit for undelivered messages, defaults to '100000'