Easy IoT is a simplest IoT Solution presented by DFRobot
The device is installed on board, there will be no network situation. So I need to realize that after the network is reconnected, the data of the disconnected time period should also be sent out, I wonder if MQTT itself has such a message flag bit function, or if there is any other way to achieve this function? The data itself is first stored in the database, and then removed from the database and sent.