class Foo: ReactiveExtensionsProvider {
    let pipe = Signal<String, NoError>.pipe()
    var bar: String = "Such bar!" {
        didSet { self.pipe.input.send(value: self.bar) }
    }
}

extension Reactive.Binds where Base: Foo {
    var bar: BindingTarget<String> {
        return self.reactive.makeBindingTarget({ $0.bar = $1 })
    }
}

extension Reactive.Signals where Base: Foo {
    var bar: Signal<String, NoError> {
        return self.base.pipe.output
    }
}

extension Reactive.Producers where Base: Foo {
    var bar: SignalProducer<String, NoError> {
        return self.reactive.signal.bar.producer.prefix(value: self.base.bar)
    }
}