cool swift rx lingering

shareReplayLatestWhileConnectedWithLinger.swift

public func shareReplayLatestWhileConnectedWithLinger(_ delayTime : RxTimeInterval, scheduler : SchedulerType = Schedulers.main) -> RxSwift.Observable<Self.E> {

    let sharedSource = self.concat(Observable.empty()
                .delaySubscription(delayTime, scheduler: scheduler))
            .shareReplayLatestWhileConnected()

    return Observable<Self.E>.create { observer in

        let sub = sharedSource.subscribe(onNext: {
            observer.on(.next($0))
        }, onError: {
            observer.on(.error($0))
        }, onCompleted: {
            observer.on(.completed)
        })

        return Disposables.create {
            _ = scheduler.scheduleRelative((), dueTime: delayTime) { _ in
                sub.dispose()
                return Disposables.create()
            }
        }
    }
}