public function getBody()
    {
        $body = '';
        if ($this->_method === 'POST' || $this->_method === 'PUT') {
            if ($this->_body === null) {
                $this->_body = $this->getPostBody();
            }
            $this->setHeader('content-length', strlen($this->_body));
            $body = $this->_body . Client::CRLF;
        }
        return $body;
    }