A media conversion can be added to your model in the registerMediaConversions-function. It should start with a call to addMediaConversion. From there on you can use any of the methods available in the API. They are all chainable.
This is the value that, when this conversation is converted to html, will be used in the loading attribute. The loading attribute is a standardised attribute that controls lazy loading behaviour of the browser. Possible values are lazy, eager, auto or null if you don't want to set any loading instruction.