Syntax
static const struct bt_mesh_model_op gen_onoff_op[] = {
{ BT_MESH_MODEL_OP_2(0x82, 0x01), 0, (void *)gen_onoff_get },
{ BT_MESH_MODEL_OP_2(0x82, 0x02), 2, (void *)gen_onoff_set },
{ BT_MESH_MODEL_OP_2(0x82, 0x03), 2, (void *)gen_onoff_set_unack },
BT_MESH_MODEL_OP_END,
};