title: Create a Publisher for a UIButton
body: <p>I'm using Combine and UIKit, and I want UIButton to be publisher.</p>
  <p>Is there any way to achieve this like RxSwift does?</p>
  <pre class="lang-swift prettyprint-override"><code>button.rx.tap.subscribe(onNext: { weak self } _ in )
  </code></pre>