title: React Native Flatlist - VirtualizedList: You have a large list that is slow to update
body: <p>I have a flat list with large content and when I am scrolling down after 10 - 15  pages  on debugger console i have getting this:</p>
  
  <blockquote>
    <p>VirtualizedList: You have a large list that is slow to update - make
    sure your renderItem function renders components that follow React
    performance best practices like PureComponent, shouldComponentUpdate,
    etc. {dt: 582, prevDt: 1651, contentLength: 15187.5}</p>
  </blockquote>
  
  <p>FYI: I have tried to use PureComponent and more ways but no one is helpful I am getting the same output in console.</p>
  
  <p>Why I am getting this and how can solve this?</p>
  
  <p>This is my code : </p>
  
  <pre><code>&lt;FlatList
      data={outfits}
      keyExtractor={(item, index) =&gt; index}
      numColumns={2}
      initialNumToRender={5}
      getItemLayout={(outfits, index) =&gt; (
         { length: 50, offset: 50 * index, index }
      )}
      extraData={this.state.extraData}
      renderItem={({item,index}) =&gt; &lt;Items item={item} index={index}/&gt;}
      onRefresh={this.handleRefresh}
      refreshing={this.state.refreshing}
      onEndReached={this.handleLoadMore}
      onEndReachedThreshold={20}
      ListFooterComponent={this.renderFooter}
  /&gt;
  </code></pre>