void Start(){
    StartCoroutine(coroutineFunction());
}
IEnumerator coroutineFunction(){
    yield return new WaitForSeconds(0.5f);
    Debug.Log("coroutine");
    yield return null;
}

void Start(){
    StartCoroutine(coroutineFunction("send massage"));
}
IEnumerator coroutineFunction(string msg){
    yield return new WaitForSeconds(0.5f);
    Debug.Log(msg);
    yield return null;
}