title: React-native sync storage solution
body: <p>In native iOS code, I could use the <code>NSUserDefaults</code> to store and fetch data, which are sync operations. In react-native the offer is to use <code>AsyncStorage</code>, but I need a solution for sync storing, like <code>NSUserDefaults</code>.
  I'm gonna use the result of data fetching to determine which screen to show, but since it's async I always get undefined when trying to fetch the persisted data. </p>