| Handler |
| Proxy |
| SessionStorageInterface | StorageInterface. |
| MetadataBag | Metadata container. |
| MockArraySessionStorage | MockArraySessionStorage mocks the session for unit tests. |
| MockFileSessionStorage | MockFileSessionStorage is used to mock sessions for functional testing when done in a single PHP process. |
| NativeSessionStorage | This provides a base class for session attribute storage. |
| PhpBridgeSessionStorage | Allows session to be started by PHP and managed by Symfony. |