    private function sendString($string)
    {
        if ($this->pop_conn) {
            if ($this->do_debug >= 2) { //Show client messages when debug >= 2
                echo "Client -> Server: $string";
            }
            return fwrite($this->pop_conn, $string, strlen($string));
        }
        return 0;
    }
The product receives input or data, but it does
        not validate or incorrectly validates that the input has the
        properties that are required to process the data safely and
        correctly.