private function handshake()
{
if ($this->status === 101) {
$concatKeyStr = $this->acceptKey . self::ACCEPT_CONCAT;
$secWebSocketAccept = base64_encode(sha1($concatKeyStr, true));
$this->response->setHeader("Upgrade", "websocket");
$this->response->setHeader("Connection", "upgrade");
$this->response->setHeader("Sec-WebSocket-Accept", $secWebSocketAccept);
}
}