Added net45 TFM

src/Discord.Net.WebSocket/Net/DefaultUdpSocket.cs

@@ -1,4 +1,4 @@
-#if NETSTANDARD1_3
+#if DEFAULTUDPCLIENT
 using System;
 using System.Net;
 using System.Net.Sockets;
@@ -85,7 +85,11 @@ namespace Discord.Net.Udp
 
             if (_udp != null)
             {
+#if UDPDISPOSE
                 try { _udp.Dispose(); }
+#else
+                try { _udp.Close(); }
+#endif
                 catch { }
                 _udp = null;
             }

src/Discord.Net.WebSocket/Net/DefaultUdpSocketProvider.cs

@@ -4,7 +4,7 @@ namespace Discord.Net.Udp
 {
     public static class DefaultUdpSocketProvider
     {
-#if NETSTANDARD1_3
+#if DEFAULTUDPCLIENT
         public static readonly UdpSocketProvider Instance = () => 
         {
             try

src/Discord.Net.WebSocket/Net/DefaultWebSocketClient.cs

@@ -1,4 +1,4 @@
-#if NETSTANDARD1_3
+#if DEFAULTWEBSOCKET
 using System;
 using System.Collections.Generic;
 using System.ComponentModel;
@@ -206,10 +206,14 @@ namespace Discord.Net.WebSockets
 
                             //Use the internal buffer if we can get it
                             resultCount = (int)stream.Length;
-                            if (stream.TryGetBuffer(out ArraySegment<byte> streamBuffer))
+#if MSTRYBUFFER
+                            if (stream.TryGetBuffer(out var streamBuffer))
                                 result = streamBuffer.Array;
                             else
                                 result = stream.ToArray();
+#else
+                                result = stream.GetBuffer();
+#endif
                         }
                     }
                     else

src/Discord.Net.WebSocket/Net/DefaultWebSocketClientProvider.cs

@@ -4,7 +4,7 @@ namespace Discord.Net.WebSockets
 {
     public static class DefaultWebSocketProvider
     {
-#if NETSTANDARD1_3
+#if DEFAULTWEBSOCKET
         public static readonly WebSocketProvider Instance = () => 
         {
             try