Несогласованность по доступности! - C#

using ExitGames.Threading;
using System.Collections.Generic;
using System.Threading;
 
namespace PhotonLIb
{
    public class World
    {
        public static readonly World Instance = new World();
 
        private List<UnityClient> Clients { get; set; }
 
        public readonly ReaderWriterLockSlim readWriteLock;
 
        public World()
        {
            Clients = new List<UnityClient>();
            readWriteLock = new ReaderWriterLockSlim();
        }
 
         public bool IsContain(string name)
        {
            using (ReadLock.TryEnter(this.readWriteLock, 1000))
            {
                return Clients.Exists(n => n.CharacterName.Equals(name));
            }
        }
 
        public void AddClient(UnityClient client)
        {
            using (WriteLock.TryEnter(this.readWriteLock, 1000))
            {
                Clients.Add(client);
            }
        }
 
        public void RemoveClient(UnityClient client)
        {
            using (WriteLock.TryEnter(this.readWriteLock, 1000))
            {
                Clients.Remove(client);
            }
        }
 
        ~World()
        {
            readWriteLock.Dispose();
        }
    }
}

using Photon.SocketServer;
using PhotonHostRuntimeInterfaces;
using ExitGames.Logging;
using System.Collections.Generic;
using PhotonLIb.Common;
using PhotonLIb.Operations;
 
namespace PhotonLIb
{
    class UnityClient : PeerBase
    {
        private readonly ILogger Log = LogManager.GetCurrentClassLogger();
 
        public string CharacterName { get; private set; }

        public UnityClient(IRpcProtocol protocol,IPhotonPeer unmanagedPeer) : base(protocol, unmanagedPeer)
        {
            Log.Info("Player connection Ip: " + unmanagedPeer.GetRemoteIP());
        }
        protected override void OnDisconnect(DisconnectReason reasonCode, string reasonDetail)
        {
            World.Instance.RemoveClient(this);
            Log.Debug("Dsconnected!");
        }
 
        protected override void OnOperationRequest(OperationRequest operationRequest, SendParameters sendParameters)
        {
            switch (operationRequest.OperationCode)
            {
                case (byte)OperationCode.Login:
                    var loginRequest = new Login(Protocol, operationRequest);

                    if (!loginRequest.IsValid)
                    {
                        SendOperationResponse(loginRequest.GetResponse(ErrorCode.InvalidParameters), sendParameters);
                        return;
                    }
 
                    CharacterName = loginRequest.CharacterName;
 
                    if(World.Instance.IsContain(CharacterName))
                    {
                        SendOperationResponse(loginRequest.GetResponse(ErrorCode.NameIsExist), sendParameters);
 
                        return;
                    }
 
                    World.Instance.AddClient(this);
 
                    var response = new OperationResponse(operationRequest.OperationCode);
                    SendOperationResponse(response, sendParameters);
 
                    Log.Info("user with name: " + CharacterName);
                    break;
                case 2:
                    if (operationRequest.Parameters.ContainsKey(1))
                    {
                        Log.Debug("recv: " + operationRequest.Parameters[1]);
                        EventData eventdata = new EventData(1);
                        eventdata.Parameters = new Dictionary<byte, object> { { 1, "response for event" } };
                        SendEvent(eventdata, sendParameters);
                    }
                    break;
                default:
                    Log.Debug("Unknown OperationRequest received!:" + operationRequest.OperationCode);
                    break;
            }
        }
    }
}