CurlMultiConnection

This is a lightweight connection class that also utilizes PHP’s cURL functionality (it uses the same set of curl-multiselect functionality that Guzzle does). This class is entirely self-contained, however, so it can offer real advantages in speed when it comes to autoloading costs (since Guzzle requires several classes to be autoloaded). It has not been as rigorously tested as Guzzle, which is why it is not default.

Once the relevant files have been autoloaded, performance between Guzzle and CurlMultiConnection is identical since they both leverage the same underlying cURL calls. It is recommended to only use CurlMultiConnection when you need very fast autoloading, such as autocompletion.