One leak fixed

ActivityPresenter.kt

class ActivityPresenter @Inject constructor(
        private val repository: SomeRepository
) : BasePresenter<ActivityView>() {

    /* removed for brevity */
        
    private val viewDisposable = CompositeDisposable()
    
    override fun attachView(view: ActivityView?) {
        super.attachView(view)

        val disposable = repository.doSomeHeavyWorkAndReturnState()
                .subscribeOn(Schedulers.io())               // send work to background thread
                .observeOn(AndroidSchedulers.mainThread())  // return results to main thread
                .subscribe { viewState.render(it) }
        viewDisposable.add(disposable)
    }
}