/**
 * Forked from github.com/google/closure-library
 * Converts a JS string to a UTF-8 "byte" array.
 * @param {string} str 16-bit unicode string.
 * @return {!Array<number>} UTF-8 byte array.
 * @see https://github.com/google/closure-library/blob/e877b1eac410c0d842bcda118689759512e0e26f/closure/goog/crypt/crypt.js
 */
export declare function convertStringToUTF8ByteArray(str: string): number[];