RxSwift endless paginator template

RxPaginator.swift

class Paginator {
    
    struct Params {
        let firstIndex: Int
    }
    
    let initParams: Params
    
    private let pageSubject = PublishSubject<Void>()
    
    init(params: Params) {
        self.initParams = params
    }
    
    func loadNext() {
        pageSubject.onNext(())
    }
    
    func start() -> Observable<[String]> {
        return load(params: initParams, accumulator: [])
    }
    
    private func load(
        params: Params,
        accumulator: [String]
    ) -> Observable<[String]> {
        return request(params.firstIndex)
            .flatMap { [pageSubject] (result) -> Observable<[String]> in
                let newParams = Params(firstIndex: params.firstIndex + result.count)
                let resultObservable = Observable.just(accumulator + result)
                let allObjects = accumulator + result
                
                return Observable.concat(
                    Observable.just(allObjects), // fetched page observable
                    Observable.never().takeUntil(pageSubject), // paginator controller observable
                    self.load(params: newParams, accumulator: allObjects)
                )
            }
    }
    
    private func request(_ firstIndex: Int) -> Observable<[String]> {
        // here has to be repository call
        let result = (firstIndex...(firstIndex+2)).map { $0.description }
        return Observable.just(result)
    }
}