NCMBのObservable化

ObservableNCMB.cs

using System;
using NCMB;
using UniRx;

namespace ObservableNCMB
{
    public static class ObservableUserAuth
    {
        /// <summary>
        /// ログインする
        /// </summary>
        public static IObservable<NCMBUser> LoginAsync(string id, string password)
        {
           return Observable.Create<NCMBUser>(observer =>
           {
               NCMBUser.LogInAsync(id, password, (NCMBException e) =>
               {
                   if (e == null)
                   {
                       observer.OnNext(NCMBUser.CurrentUser);
                       observer.OnCompleted();
                   }
                   else
                   {
                       observer.OnError(e);
                   }
               });
               return Disposable.Create(() => { ; });
           });
        }

        /// <summary>
        /// 会員登録を行う
        /// </summary>
        public static IObservable<NCMBUser> SingUpAsync(string id, string password)
        {
            return Observable.Create<NCMBUser>(observer =>
            {
                var user = new NCMBUser
                {
                    UserName = id,
                    Password = password
                };

                user.SignUpAsync((NCMBException e) =>
                {
                    if (e == null)
                    {
                        observer.OnNext(user);
                        observer.OnCompleted();
                    }
                    else
                    {
                        observer.OnError(e);
                    }
                });
                return Disposable.Create(() => {; });
            });
        }

        /// <summary>
        /// ログアウトする
        /// </summary>
        public static IObservable<Unit> LogoutAsync()
        {
            return Observable.Create<Unit>(observer =>
            {
                NCMBUser.LogOutAsync((NCMBException e) =>
                {
                    if (e == null)
                    {
                        observer.OnNext(Unit.Default);
                        observer.OnCompleted();
                    }
                    else
                    {
                        observer.OnError(e);
                    }
                });
                return Disposable.Create(() => {; });
            });
        }
    }
}