$con = new AsyncTcpConnection('ws://echo.websocket.org:80');
$con->headers = [
    'Cookie' => 'key1=value1; key2=value2'
];
$con->onConnect = function(AsyncTcpConnection $con) {
    $con->send('hello');
};
$con->onMessage = function(AsyncTcpConnection $con, $data) {
   echo $data;
};
$con->connect();