Facebook Login & Get (Username, email, userPicture)

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
using Facebook.Unity;
using System.Linq;
using Facebook.Unity.Example;
using UnityEngine.SceneManagement;

public class FBScript : MonoBehaviour
{

    public GameObject DialogLoggedIn;
    public GameObject DialogLoggedOut;
    public GameObject DialogUsername;
    public GameObject DialogEmail;
    public GameObject DialogProfilePic;

    void Awake()
    {
        FB.Init(SetInit, OnHideUnity);
    }

    void SetInit()
    {

        if (FB.IsLoggedIn)
        {
            Debug.Log("FB is logged in");
        }
        else
        {
            Debug.Log("FB is not logged in");
        }

        DealWithFBMenus(FB.IsLoggedIn);

    }

    void OnHideUnity(bool isGameShown)
    {

        if (!isGameShown)
        {
            Time.timeScale = 0;
        }
        else
        {
            Time.timeScale = 1;
        }

    }

    public void FBlogin()
    {

        List<string> permissions = new List<string>();
        permissions.Add("public_profile");
        FB.LogInWithReadPermissions(new List<string>() { "public_profile", "email" }, AuthCallBack);
    }

    void AuthCallBack(IResult result)
    {

        if (result.Error != null)
        {
            Debug.Log(result.Error);
        }
        else
        {
            if (FB.IsLoggedIn)
            {
                Debug.Log("FB is logged in");
            }
            else
            {
                Debug.Log("FB is not logged in");
            }

            DealWithFBMenus(FB.IsLoggedIn);
        }

    }

    void DealWithFBMenus(bool isLoggedIn)
    {

        if (isLoggedIn)
        {
            DialogLoggedIn.SetActive(true);
            DialogLoggedOut.SetActive(false);

            FB.API("/me?fields=first_name", HttpMethod.GET, DisplayUsername);
            FB.API("/me/picture?type=square&height=128&width=128", HttpMethod.GET, DisplayProfilePic);
            FB.API("/me?fields=email", HttpMethod.GET, DisplayEmailUser);
        }
    }

    void DisplayUsername(IResult result)
    {

        Text UserName = DialogUsername.GetComponent<Text>();

        if (result.Error == null)
        {

            UserName.text = "Hi " + result.ResultDictionary["first_name"];

        }
        else
        {
            Debug.Log(result.Error);
        }

    }

    void DisplayProfilePic(IGraphResult result)
    {

        if (result.Texture != null)
        {

            Image ProfilePic = DialogProfilePic.GetComponent<Image>();

            ProfilePic.sprite = Sprite.Create(result.Texture, new Rect(0, 0, 128, 128), new Vector2());

        }

    }

    void DisplayEmailUser(IResult result)
    {
        Text emailUser = DialogEmail.GetComponent<Text>();
        if (result.Error == null)
        {
            emailUser.text = "your email is : " + result.ResultDictionary["email"];
        }
    }

    public void changeScene(string scenename)
    {
        SceneManager.LoadScene(scenename);
    }
}