title: com.google.firebase.database.DatabaseException: Calls to setPersistenceEnabled() must be made before any other usage of FirebaseDatabase instance
body: <p>I am having a problem when I try to setPersistence in fIREBASE,can someone please explain on how to go about it,</p>
  
  <pre><code>protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.activity_meal_details);
  
          if (mDatabase == null) {
              mDatabase = FirebaseDatabase.getInstance().getReference();
              FirebaseDatabase.getInstance().setPersistenceEnabled(true);
              // ...
          }
  
  
         // FirebaseDatabase.getInstance().setPersistenceEnabled(true);
          mDatabase = FirebaseDatabase.getInstance().getReference();
  </code></pre>