AssetBucket<D>: groupAssetssubgroupTypes assets: Map<string, Asset> waiters: KEventHandler<any> errorWaiters: KEventHandler<any> lastUID: number add(name: string | null, loader: Promise): Asset<D> addLoaded(name: string | null, data: D): Asset<D> get(handle: string): Asset | undefined progress(): number getFailedAssets(): [ string, Asset ] [] waitFor(name: string, timeout: number): PromiseLike<D>