Usage of withLatestFrom in RxSwift to tackle cyclic Observable sequence

withLatestFromRxSwift.swift

let user: PublishSubject<User>()
let cart = user.startWith( ... ) // I provide a starter value for sequence
    .flatMapLatest { user -> Observable<Cart> in 
        return Observable.just(user.cart)
    }
    .map {
        ... // Do some logic here
    }
    
// Updating user for other observer
Observable.combineLatest(cart, user.asObservable()) // This combine latest cause cyclic sequence
    .flatMapLatest { (args:(cart: Cart, user: User)) -> Observable<User> in
        let _user = args.user
        _user.cart = args.cart
        return Observable.just(_user)
    }
    .bind(to: user.asObserver)
    . //DISPOSE
    
// Solution
cart.withLatestFrom(user) { (w_cart, w_user) -> (Cart, User) in // Yohoo, no more driving from User
        return (w_cart, w_user)
    }
    .flatMapLatest { (args:(cart: Cart, user: User)) -> Observable<User> in
        let _user = args.user
        _user.cart = args.cart
        return Observable.just(_user)
    }
    .bind(to: user.asObserver)
    . //DISPOSE