diff --git a/TLSharp.Core/Network/MtProtoPlainSender.cs b/TLSharp.Core/Network/MtProtoPlainSender.cs
index e468084..40bf66a 100644
--- a/TLSharp.Core/Network/MtProtoPlainSender.cs
+++ b/TLSharp.Core/Network/MtProtoPlainSender.cs
@@ -7,15 +7,15 @@ namespace TLSharp.Core.Network
 {
     public class MtProtoPlainSender
     {
-        private int _timeOffset;
-        private long _lastMessageId;
-        private readonly Random _random;
-        private readonly TcpTransport _transport;
+        private int timeOffset;
+        private long lastMessageId;
+        private Random random;
+        private TcpTransport _transport;
 
         public MtProtoPlainSender(TcpTransport transport)
         {
             _transport = transport;
-            _random = new Random();
+            random = new Random();
         }
 
         public async Task Send(byte[] data, CancellationToken token)
@@ -62,17 +62,17 @@ namespace TLSharp.Core.Network
         private long GetNewMessageId()
         {
             long time = Convert.ToInt64((DateTime.UtcNow - new DateTime(1970, 1, 1)).TotalMilliseconds);
-            long newMessageId = ((time / 1000 + _timeOffset) << 32) |
+            long newMessageId = ((time / 1000 + timeOffset) << 32) |
                                 ((time % 1000) << 22) |
-                                (_random.Next(524288) << 2); // 2^19
+                                (random.Next(524288) << 2); // 2^19
                                                             // [ unix timestamp : 32 bit] [ milliseconds : 10 bit ] [ buffer space : 1 bit ] [ random : 19 bit ] [ msg_id type : 2 bit ] = [ msg_id : 64 bit ]
 
-            if (_lastMessageId >= newMessageId)
+            if (lastMessageId >= newMessageId)
             {
-                newMessageId = _lastMessageId + 4;
+                newMessageId = lastMessageId + 4;
             }
 
-            _lastMessageId = newMessageId;
+            lastMessageId = newMessageId;
             return newMessageId;
         }
 
diff --git a/TLSharp.Core/TelegramClient.cs b/TLSharp.Core/TelegramClient.cs
index 700546c..cd8a898 100644
--- a/TLSharp.Core/TelegramClient.cs
+++ b/TLSharp.Core/TelegramClient.cs
@@ -23,12 +23,16 @@ namespace TLSharp.Core
     {
         private MtProtoSender _sender;
         private TcpTransport _transport;
-        private readonly string _apiHash = "";
-        private readonly int _apiId;
-        private List<TLDcOption> _dcOptions;
-        private readonly TcpClientConnectionHandler _handler;
+        private string _apiHash = "";
+        private int _apiId = 0;
+        private Session _session;
+        private List<TLDcOption> dcOptions;
+        private TcpClientConnectionHandler _handler;
 
-        public Session Session { get; }
+        public Session Session
+        {
+            get { return _session; }
+        }
 
         public TelegramClient(int apiId, string apiHash,
             ISessionStore store = null, string sessionUserId = "session", TcpClientConnectionHandler handler = null)
@@ -45,8 +49,8 @@ namespace TLSharp.Core
             _apiId = apiId;
             _handler = handler;
 
-            Session = Session.TryLoadOrCreateNew(store, sessionUserId);
-            _transport = new TcpTransport(Session.DataCenter.Address, Session.DataCenter.Port, _handler);
+            _session = Session.TryLoadOrCreateNew(store, sessionUserId);
+            _transport = new TcpTransport(_session.DataCenter.Address, _session.DataCenter.Port, _handler);
         }
 
        
@@ -54,14 +58,14 @@ namespace TLSharp.Core
         {
             token.ThrowIfCancellationRequested();
             
-            if (Session.AuthKey == null || reconnect)
+            if (_session.AuthKey == null || reconnect)
             {
                 var result = await Authenticator.DoAuthentication(_transport, token).ConfigureAwait(false);
-                Session.AuthKey = result.AuthKey;
-                Session.TimeOffset = result.TimeOffset;
+                _session.AuthKey = result.AuthKey;
+                _session.TimeOffset = result.TimeOffset;
             }
 
-            _sender = new MtProtoSender(_transport, Session);
+            _sender = new MtProtoSender(_transport, _session);
 
             //set-up layer
             var config = new TLRequestGetConfig();
@@ -78,32 +82,32 @@ namespace TLSharp.Core
             await _sender.Send(invokewithLayer, token).ConfigureAwait(false);
             await _sender.Receive(invokewithLayer, token).ConfigureAwait(false);
 
-            _dcOptions = ((TLConfig)invokewithLayer.Response).DcOptions.ToList();
+            dcOptions = ((TLConfig)invokewithLayer.Response).DcOptions.ToList();
         }
 
         private async Task ReconnectToDcAsync(int dcId, CancellationToken token)
         {
             token.ThrowIfCancellationRequested();
             
-            if (_dcOptions == null || !_dcOptions.Any())
+            if (dcOptions == null || !dcOptions.Any())
                 throw new InvalidOperationException($"Can't reconnect. Establish initial connection first.");
 
             TLExportedAuthorization exported = null;
-            if (Session.TLUser != null)
+            if (_session.TLUser != null)
             {
                 TLRequestExportAuthorization exportAuthorization = new TLRequestExportAuthorization() { DcId = dcId };
                 exported = await SendRequestAsync<TLExportedAuthorization>(exportAuthorization, token).ConfigureAwait(false);
             }
 
-            var dc = _dcOptions.First(d => d.Id == dcId);
+            var dc = dcOptions.First(d => d.Id == dcId);
             var dataCenter = new DataCenter (dcId, dc.IpAddress, dc.Port);
 
             _transport = new TcpTransport(dc.IpAddress, dc.Port, _handler);
-            Session.DataCenter = dataCenter;
+            _session.DataCenter = dataCenter;
 
             await ConnectAsync(true, token).ConfigureAwait(false);
 
-            if (Session.TLUser != null)
+            if (_session.TLUser != null)
             {
                 TLRequestImportAuthorization importAuthorization = new TLRequestImportAuthorization() { Id = exported.Id, Bytes = exported.Bytes };
                 var imported = await SendRequestAsync<TLAuthorization>(importAuthorization, token).ConfigureAwait(false);
@@ -127,8 +131,8 @@ namespace TLSharp.Core
                 }
                 catch(DataCenterMigrationException e)
                 {
-                    if (Session.DataCenter.DataCenterId.HasValue &&
-                        Session.DataCenter.DataCenterId.Value == e.DC)
+                    if (_session.DataCenter.DataCenterId.HasValue &&
+                        _session.DataCenter.DataCenterId.Value == e.DC)
                     {
                         throw new Exception($"Telegram server replied requesting a migration to DataCenter {e.DC} when this connection was already using this DataCenter", e);
                     }
@@ -142,7 +146,7 @@ namespace TLSharp.Core
 
         public bool IsUserAuthorized()
         {
-            return Session.TLUser != null;
+            return _session.TLUser != null;
         }
 
         public async Task<bool> IsPhoneRegisteredAsync(string phoneNumber, CancellationToken token = default(CancellationToken))
@@ -376,10 +380,10 @@ namespace TLSharp.Core
 
         private void OnUserAuthenticated(TLUser TLUser)
         {
-            Session.TLUser = TLUser;
-            Session.SessionExpires = int.MaxValue;
+            _session.TLUser = TLUser;
+            _session.SessionExpires = int.MaxValue;
 
-            Session.Save();
+            _session.Save();
         }
 
         public bool IsConnected
diff --git a/TLSharp.Core/Utils/UploadHelper.cs b/TLSharp.Core/Utils/UploadHelper.cs
index a5b0fe6..3dff1e6 100644
--- a/TLSharp.Core/Utils/UploadHelper.cs
+++ b/TLSharp.Core/Utils/UploadHelper.cs
@@ -122,14 +122,16 @@ namespace TLSharp.Core.Utils
                     Parts = partsCount
                 };
             }
-
-            return new TLInputFile
+            else
             {
-                Id = file_id,
-                Name = name,
-                Parts = partsCount,
-                Md5Checksum = GetFileHash(file)
-            };
+                return new TLInputFile
+                {
+                    Id = file_id,
+                    Name = name,
+                    Parts = partsCount,
+                    Md5Checksum = GetFileHash(file)
+                };
+            }
         }
     }
 }