如何等待协程回调执行？

Question

我想等待StartCoroutine回调执行。有人知道该怎么做吗？public float getXXX() {  var result;  StartCoroutine(YYY((r) => result = r)); // how to wait this?  return result;}private IEnumerator YYY(System.Action<float> callback) {  LinkedList<float> list = new LinkedList<float>();  while(timeleft > 0) {    timeleft -= Time.deltaTime;    list.add(transform.position.magnitude);    yield return new WaitForSeconds (WAITSPAN);  }  callback(list.max());  yeild return true;}