file_get_contents的优化替代函数

curl()比file_get_contents()快几倍.
function curl_file_get_contents($durl)
{
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $durl);
    curl_setopt($ch, CURLOPT_TIMEOUT, 5);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    $r = curl_exec($ch);
    curl_close($ch);
    return $r;
}