export declare class IndexedSet { private _items; private _itemSet; private _indexMap; insertAt(index: number, elements: T[]): void; private _chunkedInsert; delete(element: T): boolean; has(element: T): boolean; indexOf(element: T): number; get(index: number): T | undefined; get size(): number; [Symbol.iterator](): Iterator; clear(): void; find(predicate: (element: T) => boolean): T | undefined; }