src/HTTP/Request2.php
public function getBody()
    {
        if (self::METHOD_POST == $this->method
            && (!empty($this->postParams) || !empty($this->uploads))
        ) {
            if (0 === strpos($this->headers['content-type'], 'application/x-www-form-urlencoded')) {
                $body = http_build_query($this->postParams, '', '&');
                if (!$this->getConfig('use_brackets')) {
                    $body = preg_replace('/%5B\d+%5D=/', '=', $body);
                }
                // support RFC 3986 by not encoding '~' symbol (request #15368)
                return str_replace('%7E', '~', $body);

            } elseif (0 === strpos($this->headers['content-type'], 'multipart/form-data')) {
                require_once 'HTTP/Request2/MultipartBody.php';
                return new HTTP_Request2_MultipartBody(
                    $this->postParams, $this->uploads, $this->getConfig('use_brackets')
                );
            }
        }
        return $this->body;
    }
public function getBody()
    {
        if (self::METHOD_POST == $this->method
            && (!empty($this->postParams) || !empty($this->uploads))
        ) {
            if (0 === strpos($this->headers['content-type'], 'application/x-www-form-urlencoded')) {
                $body = http_build_query($this->postParams, '', '&');
                if (!$this->getConfig('use_brackets')) {
                    $body = preg_replace('/%5B\d+%5D=/', '=', $body);
                }
                // support RFC 3986 by not encoding '~' symbol (request #15368)
                return str_replace('%7E', '~', $body);

            } elseif (0 === strpos($this->headers['content-type'], 'multipart/form-data')) {
                require_once 'HTTP/Request2/MultipartBody.php';
                return new HTTP_Request2_MultipartBody(
                    $this->postParams, $this->uploads, $this->getConfig('use_brackets')
                );
            }
        }
        return $this->body;
    }
Returns the request body

@return   string|resource|HTTP_Request2_MultipartBody