simgrid::MsgHostExt::EXTENSION_ID = simgrid::s4u::Host::extension_create<simgrid::MsgHostExt>();
simgrid::s4u::Host::onCreation.connect([](simgrid::s4u::Host& host) {
host.extension_set<simgrid::MsgHostExt>(new simgrid::MsgHostExt());
simgrid::MsgHostExt::EXTENSION_ID = simgrid::s4u::Host::extension_create<simgrid::MsgHostExt>();
simgrid::s4u::Host::onCreation.connect([](simgrid::s4u::Host& host) {
host.extension_set<simgrid::MsgHostExt>(new simgrid::MsgHostExt());