title: android : mutablelivedata change is not updating the UI
body: <p>I am using MutableLiveData to store a choice user has made. The value is set from another activity. SO onResume i am calling</p>
  
  <pre><code> myMutableLivedata.value = newvale
  </code></pre>
  
  <p>But this does not update the UI unless i call a invalidateall().</p>
  
  <p>Is this expected behaviour of MutableLiveData</p>