export interface ICacheProvider {
    has(key: string): boolean;
    keys(): Array<string>;
    get<T>(key: string): T | undefined;
    getTtl(key: string): number;
    /**
     * Adds value to cache. Returns true on success.
     *
     * @param key The cache key.
     * @param value The value to cache.
     * @param ttl Time to live (in seconds).
     */
    add<T>(key: string, value: T, ttl: number): boolean;
    remove(keys: string | Array<string>): number;
    clearAll(): void;
    /**
     * Loads saved data to cache.
     * If the current instance already contains any data,
     * it clears it and replaces it with the loaded data.
     */
    load(): Promise<void>;
    /**
     * Saves data.
     */
    save(): Promise<void>;
}