disable LMIC onEvent()

src/lmic_config.h

@@ -23,6 +23,9 @@
 // time sync via LoRaWAN network, note: not supported by TTNv2
 //#define LMIC_ENABLE_DeviceTimeReq 1
 
+// use callback event handlers, not onEvent() reference
+#define LMIC_ENABLE_onEvent 0
+
 // This tells LMIC to make the receive windows bigger, in case your clock is
 // faster or slower. This causes the transceiver to be earlier switched on,
 // so consuming more power. You may sharpen (reduce) this value if you are