How to log in with multi curl?

Question

PHP

Good day. There is a parser script that goes through the pages using curl, in general, a regular parser.
Below is the function of getting the page, and if the authorization request is not authorized

function isAuth( $data ){
    return preg_match('#<a href="/site/logout" data-method="post">Logout</a>#',$data);
}
function request($url){
    $curl = curl_init();
    curl_setopt($curl, CURLOPT_COOKIESESSION, true); 
    curl_setopt($curl, CURLOPT_COOKIEFILE, "cookiefile"); 
    curl_setopt($curl, CURLOPT_RETURNTRANSFER, true); 
    curl_setopt($curl, CURLOPT_FOLLOWLOCATION, true); 
    curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
    curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, false);
    curl_setopt($curl, CURLOPT_USERAGENT, 'Mozilla/5.0 (Windows; U; Windows NT 6.0; ru; rv:1.9.1.3) Gecko/20090824 Firefox/3.5.3'); 
    curl_setopt($curl, CURLOPT_URL, $url); 
    $data = curl_exec($curl);
    if(isAuth($data)){
        return $data;
    } else {
        preg_match('/<input type="hidden" name="_csrf" value="(.*)"/Uis',$data, $login_csrf);
        $login_csrf = $login_csrf[1];
        $post = "LoginForm[username]=****&LoginForm[password]=*****&LoginForm[rememberMe]=1&_csrf=".$login_csrf."";
        curl_setopt($curl, CURLOPT_URL, 'http://yoursite.com/login');
        curl_setopt($curl, CURLOPT_POSTFIELDS, $post);
        $html = curl_exec($curl);
        unset($curl);
        return $html;
    }
}

Authorization is implemented in the script, the time has come and it is necessary to transfer the script to multi curl. I've been sitting for the third day, but I just can't log in to multi curl. Get on the right path. I tried with saving cookies, a separate curl, but apparently the knowledge is not enough, either nothing or error 400 "Failed to verify the data being sent"