phalcon控制器中setVar和Magic setter之间的区别是什么

Question

Reading the documentation of phalcon https://docs.phalconphp.com/en/3.0.0/reference/views.html I found that it's possible to pass variables from the controller to the view in 2 different ways:

1. Using setVar()

   $this->view->setVar("username", $user->username);
   $this->view->setVar("posts",    $posts;
   

2. Using the magic setter

   $this->view->username = $user->username;
   $this->view->posts    = $posts;
   

What's the difference between the two and what is the magic setter really, I couldn't find what it is.