private void Start()
    {
        Path.GetReferenceFromRoot(Firebase.Database.FirebaseDatabase.DefaultInstance.RootReference)
        .ChildAdded += OnChildAdded;
        Task.Run(() =>
        {
            var task = Path.GetReferenceFromRoot(Firebase.Database.FirebaseDatabase.DefaultInstance.RootReference)
                       .GetValueAsync();

            var result = task.Result;

            if (result.HasChildren)
            {
                foreach (var child in result.Children)
                {
                    // HandleChildAdded(child);
                }
            }
            else
            {
                //경로에 데이터 자식들이 없음
                Debug.Log("Does not have children");
            }
        });
    }
    public Task Push(object item)
    {
        if (Firebase.Auth.FirebaseAuth.DefaultInstance.CurrentUser != null)
        { //Do not commit it if the user is not logged in 유저가 로그인하지않으면 접근 못함
            return(Path.GetReferenceFromRoot(Firebase.Database.FirebaseDatabase.DefaultInstance.RootReference)
                   .Push()
                   .SetRawJsonValueAsync(JsonUtility.ToJson(item)));
        }

        return(Task.FromResult(new Object()));
    }