JMathai\PhpMultiCurl\MultiCurl::headerCallback PHP Method

    private function headerCallback($ch, $header)
    {
        $_header = trim($header);
        $colonPos = strpos($_header, ':');
        if ($colonPos > 0) {
            $key = substr($_header, 0, $colonPos);
            $val = preg_replace('/^\\W+/', '', substr($_header, $colonPos));
            $this->responses[$this->getKey($ch)]['headers'][$key] = $val;
        }
        return strlen($header);
    }