Kotlin-自定义协成

class ViewModelOne : ViewModel() {
 
    private val viewModelJob = SupervisorJob()
    private val uiScope = CoroutineScope(Dispatchers.Main + viewModelJob)
 
    val mMessage: MutableLiveData<String> = MutableLiveData()
 
    fun getMessage(message: String) {
        uiScope.launch {
            val deferred = async(Dispatchers.IO) {
                delay(2000)
                "post $message"
            }
            mMessage.value = deferred.await()
        }
    }
 
    override fun onCleared() {
        super.onCleared()
        viewModelJob.cancel()
    }
}