/**
 * Calculates the byte length of a string encoded as UTF8.
 *
 * This is a direct copy of the implemation from bcryptjs.
 * The only thing changes is the appliance of gts linting.
 *
 * @see https://github.com/dcodeIO/bcrypt.js/blob/7e2e93af99df2952253f9cf32db29aefa8f272f7/dist/bcrypt.js#L341
 * @param string The string to measure.
 * @returns The byte length of the string encoded as UTF8.
 */
export declare function utf8Length(string: string): number;