title: Have multiple elements in a FlatList header
body: <p>Is there any way to pass an array of elements to a FlatList, without a wrapper, such that I could later use <code>stickyHeaderIndices={[1]}</code> to make only the second element sticky ?</p>
  
  <p>My intent is to have a non sticky header together with a sticky toolbar and pass them to the component.</p>
  
  <p>If I try to pass the renderHeader as a function to the ListHeaderComponent such as</p>
  
  <pre><code>  renderHeader = () =&gt; {
      const { toolbar, header } = this.props;
      const arr = [header(), toolbar()];
      return arr;
    };
  </code></pre>
  
  <p>I get a </p>
  
  <pre><code>Invariant Violation: Invariant Violation: Invariant Violation: Invariant Violation: Element type is invalid: expected a string (for built-in components) or a class/function (for composite components) but got: object.
  
  Check the render method of `VirtualizedList`.
  </code></pre>
  
  <p>What would be an alternative way of achieving that behavior (i.e) have a list where only the second header gets sticky?</p>
  
  <p>Another approach I tried was to declare a scrollview  with 3 children: </p>
  
  <pre><code>The non-sticky header
  The toolbar
  The flatlist itself
  </code></pre>
  
  <p>while setting the <code>stickyHeaderIndices={[1]}</code> on the ScrollView.</p>
  
  <p>This way I got the desired visual scrolling behavior (i.e the toolbar got sticky). However, with such approach I got issues with conflicting events between the outer scrollview and the inner flatlist, so I do not know if it's a valid approach either.</p>