DeliveryMode. Transient means higher throughput but messages will not be restored on broker restart. The delivery mode of publishings is unrelated to the durability of the queues they reside on. Transient messages will not be restored to durable queues, persistent messages will be restored to durable queues and lost on non-durable queues during server restart.
This remains typed as uint8 to match Publishing.DeliveryMode. Other delivery modes specific to custom queue implementations are not enumerated here.