title: Error for setting the backgroundColor of a UITableHeaderFooterView
body: <p>I have a custom Header class for my tableviews and whenever it is used, I keep getting this error:</p>
  
  <blockquote>
    <p>[TableView] Setting the background color on UITableViewHeaderFooterView has been deprecated. Please set a custom UIView with your desired background color to the backgroundView property instead.</p>
  </blockquote>
  
  <p>Here are some things I've tried:</p>
  
  <p>I added a backgroundView in awakeFromNib() of UITableViewHeaderFooterView subclass:</p>
  
  <pre><code>override func awakeFromNib() {
      super.awakeFromNib()
      self.backgroundView = UIView(frame: self.bounds)
      self.backgroundView?.backgroundColor = UIColor(red:0.84, green:0.47, blue:0.97, alpha:1.0)
  }
  </code></pre>
  
  <p>I added a backgroundView in my tableView function that defines header sections:</p>
  
  <pre><code>func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -&gt; UIView? {
      if let headerView = tableView.dequeueReusableHeaderFooterView(withIdentifier: Header.identifier) as? Header {
  
          // Extraneous Code
  
          let backgroundView = UIView(frame: headerView.bounds)
          backgroundView.backgroundColor = UIColor(white: 0.5, alpha: 0.5)
          headerView.backgroundView = backgroundView
  
          // Extraneous code
      }
      return UIView()
  }
  </code></pre>
  
  <p>After doing each of those, I still get the error.</p>