Combine: withLatestFrom, 02

code.swift

    var cancellables = Set<AnyCancellable>()

    func setupStreams() {
        let searchStream = searchBar.searchTextField.textPublisher
            .prepend(searchBar.text!)
            .eraseToAnyPublisher()

        let sparsedSearchStream = searchStream
            .debounce(for: .seconds(0.3), scheduler: DispatchQueue.main)
            .eraseToAnyPublisher()

        sparsedSearchStream
            .sink(
                receiveValue: { searchText in
                    self.doSearching(by: searchText ?? "")
            })
            .store(in: &cancellables)
    }