title: AsyncStorage.setItem Callback Always Null
body: <p>I'm trying to use AsyncStorage to set a value and it always seems to be setting null. I've used async/await in order to do this but I've also tried to whittle down the troubleshooting to just setting a value and checking the callback and I'm still getting null. Any ideas what I'm doing wrong here? </p>
  
  <pre><code>AsyncStorage.setItem('something', 'VALUE') 
    .then((val) =&gt; { 
      this.setState({storageValue: val ? val : 'EMPTY'});
    })
  </code></pre>
  
  <p>This always gives me "EMPTY" in my state.</p>