interface Requests_Transport {
* @param string $url URL to request
* @param array $headers Associative array of request headers
* @param string|array $data Data to send either as the POST body, or as parameters in the URL for a GET/HEAD
* @param array $options Request options, see {@see Requests::response()} for documentation
* @return string Raw HTTP result
public function request($url, $headers = array(), $data = array(), $options = array());
* Send multiple requests simultaneously
* @param array $requests Request data (array of 'url', 'headers', 'data', 'options') as per {@see Requests_Transport::request}
* @param array $options Global options, see {@see Requests::response()} for documentation
* @return array Array of Requests_Response objects (may contain Requests_Exception or string responses as well)
public function request_multiple($requests, $options);
* Self-test whether the transport can be used
public static function test();