code: function(store, snapshot, url, relationship) {
          var hasManyLoaded = snapshot.hasMany(relationship.key);
  
          if (hasManyLoaded) {
            hasManyLoaded = hasManyLoaded.filter(function(item) {
              return !item.record.get('_internalModel.currentState.isEmpty');
            });
  
            if (get(hasManyLoaded, 'length')) {
              return new Ember.RSVP.Promise(function(resolve, reject) {
                reject();
              });
            }
          }
  
          return this._super(store, snapshot, url, relationship);
        }
docs: Suppress additional API calls if the relationship was already loaded via an `included` section