Close the client, received PUBACK (QoS1)

Trying to shutdown the client at some point however do not know the right time when the messaging is done, i.e. looking for the time when message has been published and PUBACK (QoS1) or PUBREC/PUBCOM (QoS2) were received.

Does anybody knows how to get status and what is the status for the finished message ? I want to put condition in my sketch to close the client.
