sFire\Cache\Adapter\Filesystem is an adapter for sFire\Cache\Cache and is based on the file system to store and retrieve data. By default, it will store all the cache in the "data/cache/shared/" folder.
To set-up the cache adapter, you need to inject the driver into a new instance of sFire\Cache\Cache. You can do so by injecting the driver into the constructor, or by calling the setDriver method.
use sFire\Cache\Cache;
$cache = new Cache('Filesystem');
use sFire\Cache\Cache;
$cache = new Cache();
$cache -> setDriver('Filesystem');
For the documentation about the usage of this driver, you can view the sFire\Cache\Cache.