I am adding another type of related products. I am adding a new method to Magento\Catalog\Model\Product\Link class by way of di.xml preference. The method also does appear in the interceptor class.
However, when I follow the execution, this call is made:
$this->_linkInstance = $productLink;
Where $productLink is returning type Magento\Catalog\Model\Product\Link\Proxy
When I look in this class at run time there is no reference to my method like there is for other relations:
public function useRelatedLinks()