How to republish an MQTT QoS 1 message when a PUBACK is not received for it?
I'm using ActiveMQ 5.14 as the MQTT Broker. When I published a QoS 1 message to a client, but the client failed to process the message and respond a PUBACK (but the TCP layer had sent an ACK already), I found that ActiveMQ would not republish the message.
Although in this case, MQTT v3.1.1 doesn't require the broker to resend the message, how can I accomplish this (with code or configuration), i.e. if an MQTT message has not been acknowledged, resend the message to the client ?