req = MC_state_get_executed_request(pair->graph_state, &value);
if (req && req->call != SIMCALL_NONE) {
req_str = simgrid::mc::request_to_string(req, value, simgrid::mc::RequestType::executed);
req = MC_state_get_executed_request(pair->graph_state, &value);
if (req && req->call != SIMCALL_NONE) {
req_str = simgrid::mc::request_to_string(req, value, simgrid::mc::RequestType::executed);