Lifecycleを使ってAutoDisposableを実現する ref: https://qiita.com/kubode/items/9d7f212219652e8439a9

ArchitectureComponents.kt

val LifecycleOwner.disposeOn: Disposable.(Lifecycle.Event) -> Unit
    get() = { disposeEvent -> disposeOn(lifecycle, disposeEvent) }

val LifecycleOwner.autoDispose: Disposable.() -> Unit
    get() = { autoDispose(lifecycle) }

FooFragment.kt

class FooFragment: Fragment() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        lifecycle.asObservable()
                .filter { it == Lifecycle.Event.ON_RESUME }
                .subscribe { toast("resumed") }
                .autoDispose()
    }
}