/**
 * cost start
 * @param label
 * @returns
 */
export declare const timeStart: <T extends string>(label: T, cb?: ((value: number) => void) | undefined) => () => number;
/**
 * cost end
 * @param label
 * @returns
 */
export declare const timeEnd: <T extends string>(label: T, cb?: ((value: number) => void) | undefined) => number;