title: Android Kotlin - AdView adSize: val cannot be reassigned
body: <pre><code>MobileAds.initialize(this) { }
  
  val adViewBottom = AdView(this)
  adViewBottom.adSize = AdSize.BANNER
  </code></pre>
  <p>This worked before I updated the library, now I get</p>
  <pre><code>val cannot be reassigned
  </code></pre>
  <p>on</p>
  <pre><code>adViewBottom.adSize
  </code></pre>
  <p>changing <code>val</code> to <code>var</code> doesn't solve it</p>