So far in this chapter, we've mostly preoccupied ourselves with render arrays and how we can expose them to the Cache API for better performance. It's now time to talk a bit about how cache entries are stored by default in Drupal and how we can interact with them ourselves in our code.
As mentioned earlier, a central interface for the cache system is the CacheBackendInterface, which is the interface any caching system needs to implement. It basically provides the methods for creating, reading, and invalidating cache entries.
As we might expect, when we want to interact with the Cache API, we use a service to retrieve an instance of the CacheBackendInterface. However, the service name we use depends on the cache bin we want to work with. Cache bins are repositories that group together cache entries based on their type. So, the aforementioned implementation...