The embedding engine now backs its graph with the SQLite store instead of
an in-memory graph, so it holds a database handle and a write-ahead-log
checkpointer that have to be released. New returns an error because
opening the store can fail, and the new Close is required: it closes the
store and removes the temp directory the zero-config constructor creates.
WithStorePath opts into a store that outlives the process, so an embedder
can index once and query the same graph on later runs.
Andrey Kumanyaev