I have managed to register a gateway and several end nodes with thing-if. When I register the end nodes I get back an endNodeThingID and an accessToken. Now I need to send states of the end nodes to the cloud. Your guide seems to be oriented at using a converter to send states via MQTT. But I was wondering, is it possible to send end node states from the gateway using the REST API instead of MQTT? My gateway code handles fetching the data from the nodes and it's a good place to use REST to send thing states to the cloud. Can I just use this call passing as parameter the endNodeThingID? If yes, which token shall I provide in this call (end node, gateway or owner)?