老版本:
let timer = Observable<Int>.interval(1, scheduler: MainScheduler.instance)
新版本
let timer = Observable<Int>.interval(DispatchTimeInterval.seconds(1), scheduler: MainScheduler.instance)
let timer = Observable<Int>.interval(1, scheduler: MainScheduler.instance)
let timer = Observable<Int>.interval(DispatchTimeInterval.seconds(1), scheduler: MainScheduler.instance)