Specifies custom configurations for your Cloud Firestore instance. You must set these before invoking any other methods.
An approximate cache size threshold for the on-disk data. If the cache grows beyond this size, Firestore will start removing data that hasn't been recently used. The size is not a guarantee that the cache will stay below that size, only that if the cache exceeds the given size, cleanup will be attempted.
The default value is 40 MB. The