title: Flow (React Native) is giving me errors for using 'this.state'
body: <p>Flow is giving me the following error whenever I try to use <code>this.state</code> in my code:</p>
  
  <blockquote>
    <p>object literal: 
    This type is incompatible with
    undefined. Did you forget to declare type parameter <code>State</code> of identifier <code>Component</code>?:</p>
  </blockquote>
  
  <p>Here is the offending code (though it happens elsewhere too):</p>
  
  <pre><code>class ExpandingCell extends Component {
      constructor(props) {
      super(props);
      this.state = {
          isExpanded: false
      };
  }
  </code></pre>
  
  <p>Any help would be much appreciated =)</p>