Why init a thread should pass nni_thr & nni_taskq_thr?

[alawn-wang]

I have been read core-code for nng, I notice that when we call nni_thr_init in nni_taskq_thread, it pass three parameters，just like this
nni_thr_init(&tq->tq_threads[i].tqt_thread, nni_taskq_thread, &tq->tq_threads[i]);
I don't know why design code as this? If just pass the third parameter nni_taskq_thread object, we also can get the nni_thr object?