It is possible, but how difficult it is depends on what you want exactly. IDBMirrorVFS isn't just MemoryAsyncVFS with persistence because it also allows multiple connections. Creating a synchronous version of IDBMirrorVFS that supports multiple connectionscould be done with theretry idea thatOPFSCoopSyncVFS uses...but that's a tricky change to code.

If all you actually want is MemoryVFS with persistence - with only one connection and durability not guaranteed - then that is a much simpler task. It is so much simpler that I would probably start from scratch instead of starting with IDBMirrorVFS and ripping things out.