RxLifecycle.kt

typealias DisposableFunction = () -> Disposable // e.g) Observable.just().subscrbie()

class RxLifecycle : LifecycleObserver {

    private var onInit: DisposableFunction? = null
    private var initDisposable: Disposable? = null

    override fun onInit() {
        // create 시점에 Stream 실행
        initDisposable = this.onInit?.invoke()
    }
    
    override fun onDeinit() {
        // destroy 시 실행된 stream 종료
        if (initDisposable?.isDisposed == false) {
            initDisposable?.dispose()
        }
    }

    fun onVisible()
    fun onInvisible()
}