title: Texfield on diffrerent page triggers StreamBuilder
body: <p>I have this <code>StreamBuilder</code> on Page1:</p>
  
  <pre><code>Widget _myFirebaseUser(BuildContext context) {
      return StreamBuilder&lt;FirebaseUser&gt;(
        stream: FirebaseAuth.instance.onAuthStateChanged,
        builder: (context, snapshot) {
          if (snapshot.hasData &amp;&amp;
              snapshot.connectionState == ConnectionState.active) {
            print('-loading user2-');
            FirebaseUser user = snapshot.data;
            if (user == null) {
              return Text('not logged in');
            }
            return ListTile(
              leading: CircleAvatar(
                backgroundImage: NetworkImage(
                  user.photoUrl,
                ),
              ),
              title: Text(user.displayName),
              subtitle: Text(user.email),
              trailing: new IconButton(
                  icon: new Icon(Icons.exit_to_app),
                  highlightColor: Colors.pink,
                  onPressed: () {
                     Navigator.of(context).pushNamed('/my-set');
                  }),
            );
          }
          return Text("loading");
        },
      );
    }
  </code></pre>
  
  <p>On Page2 I have this:</p>
  
  <pre><code>TextField(
   controller: inputNewElement,
   decoration: InputDecoration(labelText: "Add Elements"),
   onSubmitted: (elem) {
    print("Changed textfield");
   },
  ),
  </code></pre>
  
  <p>When I move to Page2 and edit my TextField I can see the logs from previous page. I have tried <code>StreamBuilder</code> and <code>FutureBuilder</code> with same result.</p>
  
  <p>How can avoid this behaviour?</p>