How do I print the author details for a node? In particular, I am interested to the following values.

* Author picture
* Name
* Description

In Drupal 7, I would use this code.

```
<?php print $author_data['picture'];?>
<?php print $author_data['name']; ?>
<?php print $author_data['description']?>

```

What is the equivalent in Drupal 8?