read_login_data()
read_login_data(\Symfony\Component\HttpFoundation\Request  $request) : Array
                This call should process the current authentication credentials and return the username / password pair that should be tried to authentication or null for anonymous access.
Parameters
| \Symfony\Component\HttpFoundation\Request | $request | The request we're reading from  | 
                            
Returns
Array —A simple associative array with the two indexes 'username' and 'password' holding the information read by the driver or null if no information could be read.