如何停止多次触发LiveData事件

class MyViewModel : ViewModel() {
    private val _myLiveData = MutableLiveData<String>()
    val myLiveData: LiveData<String> get() = _myLiveData

    fun init() {
        // 移除旧的观察者
        myLiveData.removeObservers(lifecycleOwner)
        // 添加新的观察者
        myLiveData.observe(lifecycleOwner, Observer { value ->
            // 处理数据变化
        })
    }
}

class MyViewModel : ViewModel() {
    private val _source1 = MutableLiveData<String>()
    private val _source2 = MutableLiveData<String>()
    private val _mergedLiveData = MediatorLiveData<String>()

    val mergedLiveData: LiveData<String> get() = _mergedLiveData

    init {
        _mergedLiveData.addSource(_source1) { value ->
            _mergedLiveData.value = value
        }
        _mergedLiveData.addSource(_source2) { value ->
            _mergedLiveData.value = value
        }
    }

    fun updateSource1(value: String) {
        _source1.value = value
    }

    fun updateSource2(value: String) {
        _source2.value = value
    }
}

class MyViewModel : ViewModel() {
    private val _myLiveData = MutableLiveData<String>()
    val myLiveData: LiveData<String> get() = _myLiveData.distinctUntilChanged()

    fun updateData(value: String) {
        _myLiveData.value = value
    }
}