final protected function createHeader()
    {
        $host = $this->host;
        if ($host === '127.0.0.1' || $host === '0.0.0.0')
        {
            $host = 'localhost';
        }

        return "GET {$this->path} HTTP/1.1" . "\r\n" .
        "Origin: null" . "\r\n" .
        "Host: {$host}:{$this->port}" . "\r\n" .
        "Sec-WebSocket-Key: {$this->key}" . "\r\n" .
        "User-Agent: ".self::UserAgent."/" . self::VERSION . "\r\n" .
        "Upgrade: Websocket" . "\r\n" .
        "Connection: Upgrade" . "\r\n" .
        "Sec-WebSocket-Protocol: wamp" . "\r\n" .
        "Sec-WebSocket-Version: 13" . "\r\n" . "\r\n";
    }