Posted when the asset manager has loaded all the assets in its queue.
Note that this event does NOT necessarily mean that all asset loading is complete. Rather is just means that the asset manager has loaded everything in its queue.
For example, when the MPF-MC boots, it will load the assets it is configured to load on start. However, if the MPF MC is started but MPF is not, then the MPF MC will load its assets and then post this asset_loading_complete event when it’s done. Then when MPF is started and connects, MPF will need to load its own assets, which means the MPF MC will post more loading_assets and then a final asset_loading_complete event a second time for the MPF-based assets.
This event does not have any keyword arguments