fetch method
Fetch the item with the given id
from the API.
Implementers should ensure this method updates the cache.
Implementation
@override
Future<Entitlement> fetch(Snowflake id) async {
final entitlements = await list(before: Snowflake(id.value + 1));
return entitlements.firstWhere(
(entitlement) => entitlement.id == id,
orElse: () => throw EntitlementNotFoundException(applicationId, id),
);
}