title: Realm what is RealmObject.isValid()?
body: <p>Hi everybody i have somes problems or bug..
  Have 1 year working with <code>Realm</code> i understand realm use threads ok..</p>
  
  <p>what does it mean make isValid() for example</p>
  
  <pre><code>User user extends RealmObject
  
  user.isValid() ?
  </code></pre>
  
  <p>What is my result ?</p>