Snapshotting of global state, factored out of PHPUnit into a stand-alone component.
You can add this library as a local, per-project dependency to your project using [Composer](https://getcomposer.org/):
composer require sebastian/global-state
If you only need this library during development, for instance to run your project's test suite, then you should add it as a development-time dependency:
composer require --dev sebastian/global-state