title: Update UIKeyboardAppearance while keyboard is shown
body: <p>Cocoa Touch allows to change the keyboard appearance by setting the keyboardAppearance property of the UITextInputTraits protocol, which is implemented in the UITextField and UITextView classes. </p>
  
  <p>It seems that updating the keyboardAppearance property while the keyboard is already on the screen do not update the keyboard appearance.</p>
  
  <p>As a workaround I was thinking to dismiss the keyboard and reopen it. Is there a better way to solve the issue?</p>