export declare class MultiCacheState {
    /**
     * Keys that are currently being revalidated.
     */
    keysBeingRevalidated: Set<string>;
    /**
     * Add a key that is currently being revalidated.
     */
    addKeyBeingRevalidated(key: string): void;
    /**
     * Remove a key from being revalidated.
     */
    removeKeyBeingRevalidated(key: string): void;
    /**
     * Check if a key is currentl being revalidated.
     */
    isBeingRevalidated(key: string): boolean;
}