[ NoWrapper ]
public virtual AssetLoadingReturn start_loading () throws Error
A method to be called when an asset is being requested asynchronously.
This will be after the properties of the asset have been set, so it is tasked with (re)loading the 'state' of the asset. The return value should indicated whether the loading is complete, is carrying on asynchronously, or an error occurred. The default implementation will simply return that loading is already complete (the asset is already in a usable state after the properties have been set).