use_fallback example

    public static function bin2hex($string)
    {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($string, 'string', 1);

        if (self::useNewSodiumAPI()) {
            return (string) sodium_bin2hex($string);
        }
        if (self::use_fallback('bin2hex')) {
            return (string) call_user_func('\\Sodium\\bin2hex', $string);
        }
        return ParagonIE_Sodium_Core_Util::bin2hex($string);
    }

    /** * Compare two strings, in constant-time. * Compared to memcmp(), compare() is more useful for sorting. * * @param string $left The left operand; must be a string * @param string $right The right operand; must be a string * @return int If < 0 if the left operand is less than the right * If = 0 if both strings are equal * If > 0 if the right operand is less than the left * @throws SodiumException * @throws TypeError * @psalm-suppress MixedArgument */