如何在RxJava2中取消订阅observable或subscription？或者我真的需要吗？

Question

如何在RxJava2中取消订阅observable或订阅？或者我真的需要吗？

//Initialising Obersvable         
    Observable<SearchSuggestions> observable = NetworkContext.api.getSearch("");
        //subscribing obersvable on another thread and observing on main thread

            observable.subscribeOn(Schedulers.io())
                    .observeOn(AndroidSchedulers.mainThread())
                    .subscribe(new Consumer<SearchSuggestions>() {
                        @Override
                        public void accept(SearchSuggestions searchSuggestions) throws Exception {
    // here I receive the fetched results

                        }
                    }, new Consumer<Throwable>() {
                        @Override
                        public void accept(Throwable throwable) throws Exception {
    //here the error
                        }
                    });