Root & Stores

FMTC uses a root and stores to structure its data. In general, a single root exists (which uses a single backend), which contains multiple named stores. Cached tiles can belong to multiple stores, which reduces duplication and maximizes flexibility.

The structures use the ambient backend when a method is invoked on it, not at construction time.

Therefore, it is possible to construct an FMTCStore/FMTCRoot before initialisation, but 'using' any methods on it will throw RootUnavailable.