call_trace_func  3499 thread.c       static void call_trace_func(rb_event_flag_t, VALUE data, VALUE self, ID id, VALUE klass);
call_trace_func  3547 thread.c           rb_remove_event_hook(call_trace_func);
call_trace_func  3557 thread.c           rb_add_event_hook(call_trace_func, RUBY_EVENT_ALL, trace);