如何在NVActivityIndicatorView中使用RxSwift？

import RxSwift
import RxCocoa
import NVActivityIndicatorView

let activityIndicatorSubject = PublishSubject<Bool>()

let activityIndicatorView = NVActivityIndicatorView(frame: CGRect(x: 0, y: 0, width: 50, height: 50))
activityIndicatorView.color = .red

activityIndicatorSubject
    .observeOn(MainScheduler.instance)
    .subscribe(onNext: { [weak self] isLoading in
        if isLoading {
            self?.activityIndicatorView.startAnimating()
        } else {
            self?.activityIndicatorView.stopAnimating()
        }
    })
    .disposed(by: disposeBag)

activityIndicatorSubject.onNext(true) // 启动动画
activityIndicatorSubject.onNext(false) // 停止动画