Getting user info using Facebook SDK 4.0.1

I am working to upgrade facebook ios SDK to 4.0.1 from 3.X

In login view i use this code,

override func viewDidLoad() {
    super.viewDidLoad()

    self.fbLoginButton.delegate = self
    FBSDKProfile.enableUpdatesOnAccessTokenChange(true)

    if (FBSDKAccessToken.currentAccessToken() != nil)
    {
    var fbuserid = FBSDKAccessToken.currentAccessToken().userID
        //Get users info (email,firstname,lastname,username)
    }

    self.fbLoginButton.readPermissions = ["public_profile", "email", "user_friends","publish_stream","user_location","user_about_me", "user_photos", "user_website"]

}

I need to get user's info such as email,firstname,lastname,username

Anyone knows how to do that?