-surf_callback(void, Cpu*) cpuCreatedCallbacks;
-surf_callback(void, Cpu*) cpuDestructedCallbacks;
-surf_callback(void, Cpu*, e_surf_resource_state_t, e_surf_resource_state_t) cpuStateChangedCallbacks;
-surf_callback(void, CpuAction*, e_surf_action_state_t, e_surf_action_state_t) cpuActionStateChangedCallbacks;
+simgrid::surf::signal<void(CpuAction*, e_surf_action_state_t, e_surf_action_state_t)> cpuActionStateChangedCallbacks;
+