Added some TCP wrapper classes for testability

AMWD.Protocols.Modbus.Tcp/Utils/SocketWrapper.cs

@@ -0,0 +1,29 @@
+using System;
+using System.Net.Sockets;
+
+namespace AMWD.Protocols.Modbus.Tcp.Utils
+{
+	internal class SocketWrapper : IDisposable
+	{
+		private Socket _socket;
+
+		public SocketWrapper(Socket socket)
+		{
+			_socket = socket;
+		}
+
+		/// <inheritdoc  cref="Socket.DualMode" />
+		public virtual bool DualMode
+		{
+			get => _socket.DualMode;
+			set => _socket.DualMode = value;
+		}
+
+		/// <inheritdoc  cref="Socket.IsBound" />
+		public virtual bool IsBound
+			=> _socket.IsBound;
+
+		public virtual void Dispose()
+			=> _socket.Dispose();
+	}
+}