title: Flutter: how to logout of facebook and get the login dialog
body: <p>I am authentication with Facebook from my flutter app. This is working , however , the login dialog only shows the first time .</p>
  
  <p>After I logoff I don't get the login prompt again.. The only method to see the login dialog again is go  the FB and logoff</p>
  
  <p>Can please let me know I can logoff of facebook from my flutter app and show the login dialog..</p>
  
  <p>Google auth work great.. I see the login dialog</p>
  
  <p>Logoff code</p>
  
  <pre><code>Future&lt;void&gt; signOut() async {
      await googleSignIn.signOut();
      await facebookLogin.logOut();
      await FirebaseAuth.instance.signOut();
      await _firebaseAuth.signOut();
      randstadUserProfile = null;
      firebaseUser = null;
    }
  </code></pre>