TAILQ_INSERT_HEAD 2969 opal/mca/event/libevent2022/libevent/buffer.c 	TAILQ_INSERT_HEAD(&buffer->callbacks, e, next);
TAILQ_INSERT_HEAD 2591 opal/mca/event/libevent2022/libevent/event.c 	TAILQ_INSERT_HEAD(&ctl->events, ev,