/**
 * Checks if a string contains characters that require UTF-16BE encoding.
 *
 * PDFDocEncoding can represent:
 * - ASCII characters (0-127)
 * - Special PDF characters (mapped from specific Unicode chars to bytes 128-159)
 * - ISO Latin-1 characters (160-255)
 *
 * Anything outside this range requires UTF-16BE encoding.
 *
 * @param str - The string to check
 * @returns True if the string contains characters that cannot be represented in PDFDocEncoding
 *
 * @example
 * ```typescript
 * needsUnicodeEncoding('Hello') // Returns false (ASCII)
 * needsUnicodeEncoding('Café') // Returns false (ISO Latin-1)
 * needsUnicodeEncoding('Test • item') // Returns false (special PDF char)
 * needsUnicodeEncoding('Hello 世界') // Returns true (needs UTF-16BE)
 * ```
 */
export declare function needsUnicodeEncoding(str: string): boolean;