public function getHeaders()
    {
        if ($this->_headers === null) {
            $this->_headers = new HeaderCollection();
            foreach ($this->swooleRequest->server as $name => $value) {
                if (strncmp($name, 'HTTP_', 5) === 0) {
                    $name = str_replace(' ', '-', ucwords(strtolower(str_replace('_', ' ', substr($name, 5)))));
                    $this->_headers->add($name, $value);
                }
            }
        }
        return $this->_headers;
    }