</td></tr><tr><td>QoS Level</td><td>At most once (0) |At least once (1) | Exactly once (2); Default: '''At most once (0)'''</td><td>The publish/subscribe QoS level used for this topic | </td></tr><tr><td>QoS Level</td><td>At most once (0) |At least once (1) | Exactly once (2); Default: '''At most once (0)'''</td><td>The publish/subscribe QoS level used for this topic |