Как подключиться к socket.io серверу через прокси-сервер с помощью PHP?

Я пытаюсь подключиться к socket.io серверу через прокси-сервер с помощью PHP, но получаю некорректный ответ (ниже заголовки, которые я получаю в ответ):

HTTP/1.1 400 Bad Request
Content-Type: application/json
Access-Control-Allow-Origin: *
Date: Mon, 06 Nov 2017 18:10:46 GMT
Connection: Close
Proxy-Connection: Close

{"code":3,"message":"Bad request"}

Мой код:

<?php
ob_implicit_flush();

function generateKey($length = 16) {
    $c = 0;
    $tmp = '';

    while ($c++ * 16 < $length) {
        $tmp .= md5(mt_rand(), true); 
    }

    return base64_encode(substr($tmp, 0, $length));
}

function hybi10Encode($payload, $type = 'text', $masked = true)
    {
        $frameHead = array();
        $payloadLength = strlen($payload);
        switch ($type) {
            case 'text':
                $frameHead[0] = 129;
                break;
            case 'close':
                $frameHead[0] = 136;
                break;
            case 'ping':
                $frameHead[0] = 137;
                break;
            case 'pong':
                $frameHead[0] = 138;
                break;
        }
        if ($payloadLength > 65535) {
            $payloadLengthBin = str_split(sprintf('%064b', $payloadLength), 8);
            $frameHead[1] = ($masked === true) ? 255 : 127;
            for ($i = 0; $i < 8; $i++) {
                $frameHead[$i + 2] = bindec($payloadLengthBin[$i]);
            }
            if ($frameHead[2] > 127) {
                $this->close(1004);
                return false;
            }
        } elseif ($payloadLength > 125) {
            $payloadLengthBin = str_split(sprintf('%016b', $payloadLength), 8);
            $frameHead[1] = ($masked === true) ? 254 : 126;
            $frameHead[2] = bindec($payloadLengthBin[0]);
            $frameHead[3] = bindec($payloadLengthBin[1]);
        } else {
            $frameHead[1] = ($masked === true) ? $payloadLength + 128 : $payloadLength;
        }
        foreach (array_keys($frameHead) as $i) {
            $frameHead[$i] = chr($frameHead[$i]);
        }
        if ($masked === true) {
            $mask = array();
            for ($i = 0; $i < 4; $i++) {
                $mask[$i] = chr(rand(0, 255));
            }
            $frameHead = array_merge($frameHead, $mask);
        }
        $frame = implode('', $frameHead);
        for ($i = 0; $i < $payloadLength; $i++) {
            $frame .= ($masked === true) ? $payload[$i] ^ $mask[$i % 4] : $payload[$i];
        }
        return $frame;
}

$protocol = "http://";
$host = "myip";
$port = "myhost";
$path = "/socket.io/?EIO=2&transport=websocket";

$proxy = explode("@", "proxyip:proxyport@proxyusr:proxypwd");
$proxy_host = explode(":", $proxy[0]);
$proxy_auth = base64_encode($proxy[1]);

$key = generateKey();

$socket = fsockopen($proxy_host[0], $proxy_host[1]);

$headers = "GET {$protocol}{$host}:{$port}{$path} HTTP/1.1\r\n";
$headers.= "Host: {$proxy[0]}\r\n";
$headers.= "Proxy-Authorization: Basic {$proxy_auth}\r\n";
$headers.= "Proxy-Connection: Keep-Alive\r\n";
$headers.= "Upgrade: WebSocket\r\n";
$headers.= "Connection: Upgrade\r\n";
$headers.= "Sec-WebSocket-Key: $key\r\n";
$headers.= "Sec-WebSocket-Version: 13\r\n";
$headers.= "Origin: *\r\n\r\n";

fwrite($socket, $headers);

$result = fread($socket, 10000);
print_r($result);
while (!feof($socket)) {
    $data = fgets($socket, 128);

    fwrite($socket, hybi10Encode('42["action",{"action":1}]'));
}

fclose($socket);
?>