UITextField no longer has the function distinctUntilChanged()

Question

Since upgrading to Swift 3 with pod 'RxSwift', '~> 3.0' and 'RxCocoa', '~> 3.0', it seems that distinctUntilChanged() is no longer available for UITextField. I want to use it as below. Do I need to write and extension for UITextField or am I missing something since the update from Swift 2?

 textField.rx.text.distinctUntilChanged().subscribe(onNext: {text in print("\(text)")}