/**
 * Converts an UTF-8 string to an ArrayBuffer.
 * @param {string} str String.
 * @returns {ArrayBuffer} ArrayBuffer.
 */
export function utf8ToBuf(str: string): ArrayBuffer;
/**
 * Converts an ArrayBuffer to an UTF-8 string.
 * @param {ArrayBuffer} buf ArrayBuffer.
 * @returns {string} String.
 */
export function utf8FromBuf(buf: ArrayBuffer): string;