It is highly recommended that you provide users that signed in with Google the
ability to disconnect their Google account from your app. If the user deletes
their account, you must delete the information that your app obtained from the
Google APIs.

The following code example demonstrates how to programmatically revoke access
tokens that your app was granted on behalf of the user and to disconnect the
user's account from your app.

### Swift

    GIDSignIn.sharedInstance.disconnect { error in
        guard error == nil else { return }

        // Google Account disconnected from your app.
        // Perform clean-up actions, such as deleting data associated with the
        //   disconnected account.
    }

### Objective-C

    [GIDSignIn.sharedInstance disconnectWithCompletion:^(NSError * _Nullable error) {
        if (error) { return; }

        // Google Account disconnected from your app.
        // Perform clean-up actions, such as deleting data associated with the
        //   disconnected account.
    }];

The `disconnectWithCompletion:` method signs the user out in addition to
disconnecting their account and revoking tokens. You must not sign the user out
before calling `disconnectWithCompletion:`.

You can then respond to the successful disconnection within the callback block
and trigger any appropriate logic in your app or your back-end code.