Increase Retrival Performance

[MentalGear]

Thank you for the awesome library!
Could you give me your opinion on this proposal.

• Use in-memory for Performance
  I'd like to propose the option to use in-memory processing to further improve on performance.
  indexDB could still be used as the default, but when memory is used for processing, all data is at the beginning loaded into memory. Here's a graph showing the difference.

• Export Data Serialization
  Also, it would make sense to have a serialization method to allow saving the data to other places instead of indexDB, like another user defined place (e.g. RxDB),
  https://rxdb.info/rx-storage-opfs.html