title: Custom navigation back button with custom title in swift3
body: <p>I need to implement the navigation bar with custom back image and custom title. For example: if i am in "Login with facebook" page i need to show the "Login with facebook" besides the custom back image. For this i am following the code like this:</p>
  
  <pre><code>let yourBackImage = UIImage(named: "back_button_image")
  self.navigationController?.navigationBar.backIndicatorImage = yourBackImage
  self.navigationController?.navigationBar.backIndicatorTransitionMaskImage = yourBackImage
  self.navigationController?.navigationBar.backItem?.title = "Custom"
  </code></pre>
  
  <p>But I am getting the output like this:</p>
  
  <p><a href="https://i.stack.imgur.com/8s54M.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/8s54M.png" alt="enter image description here"></a></p>
  
  <p>Note: The title is of the current page.</p>
  
  <p>How to achieve this?</p>