Returns a reference to the loader's [`IndirectionTable`]. When a user fetches an asset by LoadHandle, implementors of [`AssetStorage`] should resolve LoadHandles where [`LoadHandle::is_indirect`] returns true by using [`IndirectionTable::resolve`]. IndirectionTable is Send + Sync + Clone so that it can be retrieved once at startup, then stored in implementors of [`AssetStorage`].
(&self)