export interface KeyBuilder {
    getKey(): string | undefined;
    /**
     * @deprecated Use .setKey() instead
     */
    key(key: string): this;
    setKey(key: string): this;
}
export declare class KeyHelper {
    #private;
    getKey(): string | undefined;
    setKey(key: string): void;
    build(): {
        key: string;
    } | {
        key?: undefined;
    };
}