The DS.Model `relationships` property is unavailable in record's `init`?

Official documentation for DS.Model describes:

• method eachRelationship


• property relationships

When i do:

App.Parent = DS.Model.extend({
  children: DS.hasMany('child'),
  init: function() {
    this._super();

    this.eachRelationship(function(foo, bar, baz) {
      console.log('each relationship', foo, bar, baz);
    });
  }
});

...it prints out the children relationship.

However, when i do:

App.Parent = DS.Model.extend({
  children: DS.hasMany('child'),
  init: function() {
    this._super();

    console.log('realtionships', this.get('relationships'));
  }
});

...it prints undefined!

Why? How do i access the relationships property during record initialization, without reverting to the eachRelationship method?

Demo: http://ift.tt/1xtxvwg