Unloads assets that are not used.
An asset is deemed to be unused if it isn't reached after walking the whole game object hierarchy, including script components. Static variables are also examined.
By passing in an additional parameter, asset references from script properties and static variables can optionaly be ignored. The unloaded assets will be loaded again on first use.
This method differs from Resources.UnloadUnusedAssets in that it will wait for asset garbage collection to finish before returning.
See Also: Resources.UnloadUnusedAssets.