Add server implementation

MQTTnet.Core/Server/MqttServerOptions.cs

@@ -0,0 +1,17 @@
+using System;
+using MQTTnet.Core.Packets;
+using MQTTnet.Core.Protocol;
+
+namespace MQTTnet.Core.Server
+{
+    public class MqttServerOptions
+    {
+        public int Port { get; set; } = 1883;
+
+        public int ConnectionBacklog { get; set; } = 10;
+
+        public TimeSpan DefaultCommunicationTimeout { get; set; } = TimeSpan.FromSeconds(10);
+
+        public Func<MqttConnectPacket, MqttConnectReturnCode> ConnectionValidator { get; set; }
+    }
+}