Add nuget support

Frameworks/MQTTnet.NetCoreApp/MqttTcpChannel.cs

@@ -0,0 +1,81 @@
+using System;
+using System.Net.Sockets;
+using System.Threading.Tasks;
+using MQTTnet.Core.Channel;
+using MQTTnet.Core.Client;
+using MQTTnet.Core.Exceptions;
+
+namespace MQTTnet
+{
+    public class MqttTcpChannel : IMqttCommunicationChannel, IDisposable
+    {
+        private readonly Socket _socket;
+
+        public MqttTcpChannel()
+        {
+            _socket = new Socket(SocketType.Stream, ProtocolType.Tcp);
+        }
+
+        public MqttTcpChannel(Socket socket)
+        {
+            _socket = socket ?? throw new ArgumentNullException(nameof(socket));
+        }
+
+        public async Task ConnectAsync(MqttClientOptions options)
+        {
+            try
+            {
+                await _socket.ConnectAsync(options.Server, options.Port);
+            }
+            catch (SocketException exception)
+            {
+                throw new MqttCommunicationException(exception);
+            }
+        }
+
+        public async Task DisconnectAsync()
+        {
+            try
+            {
+                _socket.Dispose();
+                await Task.FromResult(0);
+            }
+            catch (SocketException exception)
+            {
+                throw new MqttCommunicationException(exception);
+            }
+        }
+
+        public async Task WriteAsync(byte[] buffer)
+        {
+            if (buffer == null) throw new ArgumentNullException(nameof(buffer));
+
+            try
+            {
+                await _socket.SendAsync(new ArraySegment<byte>(buffer), SocketFlags.None);
+            }
+            catch (SocketException exception)
+            {
+                throw new MqttCommunicationException(exception);
+            }
+        }
+
+        public async Task ReadAsync(byte[] buffer)
+        {
+            try
+            {
+                var buffer2 = new ArraySegment<byte>(buffer);
+                await _socket.ReceiveAsync(buffer2, SocketFlags.None);
+            }
+            catch (SocketException exception)
+            {
+                throw new MqttCommunicationException(exception);
+            }
+        }
+
+        public void Dispose()
+        {
+            _socket?.Dispose();
+        }
+    }
+}