if (not engine->get_netzone_root()) {
engine->set_netzone_root(&piface_);
/* root netzone set, initialize models */
simgrid::s4u::Engine::on_platform_creation();
if (not engine->get_netzone_root()) {
engine->set_netzone_root(&piface_);
/* root netzone set, initialize models */
simgrid::s4u::Engine::on_platform_creation();