title: Why can't I signout of Google in iOS?
body: <p>In iOS, I'm developing Google login using Google SDK. But I can't sign out after sign in. After calling signOut method, there is no any react.
  Please help me.</p>
  
  <pre><code>[[GIDSignIn sharedInstance] signOut];
  [[GIDSignIn sharedInstance] disconnect];
  </code></pre>