app: Heart Rate Sensor example started. app: Fast advertising. app: pm_evt_handler 0 app: Connected to a previously bonded device. app: pm_evt_handler 15 app: Connected. app: GATT ATT MTU on connection 0x0 changed to 23. app: pm_evt_handler 8 app: pm_evt_handler 1 app: pm_evt_handler 2 app: Connection secured: role: 1, conn_handle: 0x0, procedure: 0.