Php : Curl With Headers Not Working

我正在尝试在curl中设置标题。但我的卷曲是不工作，如果我使用头。下面是我的代码。

   $ch = curl_init();
    $headers = array("Content-Type: multipart/form-data; boundary=---------------------------643932844140921187526840362", "Content-Length: 1927");
    curl_setopt($ch,CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
    curl_setopt($ch, CURLOPT_REFERER, 'http://domain.com/submit/');
    curl_setopt($ch, CURLOPT_RETURNTRANSFER,true);
    curl_setopt($ch, CURLOPT_USERAGENT, "Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US) AppleWebKit/525.13 (KHTML, like Gecko) Chrome/0.A.B.C Safari/525.13");
    curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
    curl_setopt($ch,CURLOPT_COOKIEJAR, "cookie.txt");
    curl_setopt($ch,CURLOPT_COOKIEFILE, "cookie.txt");
    curl_setopt($ch,CURLOPT_POST, count($fields));
    curl_setopt($ch,CURLOPT_POSTFIELDS, $fields_string);
    $result = curl_exec($ch); 
    $last = curl_getinfo($ch, CURLINFO_EFFECTIVE_URL);
    return array($result,$last);
    curl_close($ch);

但如果我删除下面的代码，代码工作正常。

$headers = array("Content-Type: multipart/form-data; boundary=---------------------------643932844140921187526840362", "Content-Length: 1927");
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);

这是设置标题的正确方法吗?还是我错了?