Link to dangers of shared prefs

[kurtisnelson]

Might be worthwhile explaining or pointing to an explanation of why not use SharedPrefs

Originally posted by @jbarr21 in https://github.com/uber/simple-store/pull/25#issuecomment-494649681

[kurtisnelson]

Also compare to room and SQL.

[kawpiie]

@kurtisnelson Will this make this project obsolete? If not why?

[kurtisnelson]

The AndroidX shared preferences replacement will likely be backed by SQLite. This keeps the library easy to use for new developers but has a significant performance hit both on memory and CPU. SimpleStore uses the fundamental JVM file APIs and has zero overhead until opened.