import RxTheme
protocol Theme {
    var backgroundColor: UIColor { get }
    var textColor: UIColor { get }
}
struct LightTheme: Theme {
    let backgroundColor = .white
    let textColor = .black
}
struct DarkTheme: Theme {
    let backgroundColor = .black
    let textColor = .white
}
enum ThemeType: ThemeProvider {
    case light, dark
    var associatedObject: Theme {
        switch self {
        case .light:
            return LightTheme()
        case .dark:
            return DarkTheme()
        }
    }
}
let themeService = ThemeType.service(initial: .light)

// Bind stream to a single attribute
// RxTheme would automatically manage the lifecycle of the binded stream
view.theme.backgroundColor = themeService.attribute { $0.backgroundColor }

themeService.switch(.dark)
// When this is triggered by some signal, you can use:
someSignal.bind(to: themeService.switcher)

// Current theme type
themeService.type
// Theme type stream
themeService.typeStream