perf_event__synthesize_extra_attr
err = perf_event__synthesize_extra_attr(&rec->tool,
err = perf_event__synthesize_extra_attr(tool, evlist, process, attrs);
int perf_event__synthesize_extra_attr(const struct perf_tool *tool, struct evlist *evsel_list, perf_event__handler_t process, bool is_pipe);