| Exception |
| FromConfigInterface | Interfaces that adds a factory method which is used to instantiate a class from an array of configuration options. |
| HasDispatcherInterface | Holds an event dispatcher |
| ToArrayInterface | An object that can be represented as an array |
| AbstractHasDispatcher | Class that holds an event dispatcher |
| Collection | Key value pair collection object |
| Event | Default event for Guzzle notifications |
| Version | Guzzle version information |