override fun tryLogin(username: String, password: String) {
                mLoginInteractor.login(username, password)
                        .subscribeOn(Schedulers.newThread())
                        .observeOn(AndroidSchedulers.mainThread())
                        .subscribe(object : Subscriber<User>(){
        [...]
        }

override fun login(username: String, password: String) =
 mRetrofit.create(ApiClient::class.java).login()

override fun tryLogin(username: String, password: String) {
                mLoginInteractor.login(username, password)
                        .subscribe(object : Subscriber<User>(){
        [...]
        }

override fun login(username: String, password: String) =
     mRetrofit.create(ApiClient::class.java).login()
.subscribeOn(Schedulers.newThread())
.observeOn(AndroidSchedulers.mainThread())