Fixed a few json settings (such as dates deserializing to UTC), and use cached jsonserializers in more places.

src/Discord.Net.Audio/Net/VoiceSocket.cs

@@ -10,6 +10,7 @@ using System;
 using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Diagnostics;
+using System.IO;
 using System.Linq;
 using System.Net;
 using System.Net.Sockets;
@@ -402,7 +403,11 @@ namespace Discord.Net.WebSockets
         protected override async Task ProcessMessage(string json)
         {
             await base.ProcessMessage(json).ConfigureAwait(false);
-            var msg = JsonConvert.DeserializeObject<WebSocketMessage>(json);
+
+            WebSocketMessage msg;
+            using (var reader = new JsonTextReader(new StringReader(json)))
+                msg = _serializer.Deserialize(reader, typeof(WebSocketMessage)) as WebSocketMessage;
+            
             var opCode = (OpCodes)msg.Operation;
             switch (opCode)
             {

src/Discord.Net/Net/Rest/JsonRestClient.cs

@@ -1,22 +1,23 @@
 using Discord.Logging;
 using Newtonsoft.Json;
+using System.IO;
 
 namespace Discord.Net.Rest
 {
     public class JsonRestClient : RestClient
     {
-        private JsonSerializerSettings _deserializeSettings;
+        private JsonSerializer _serializer;
 
         public JsonRestClient(DiscordConfig config, string baseUrl, Logger logger)
             : base(config, baseUrl, logger)
         {
-            _deserializeSettings = new JsonSerializerSettings();
+            _serializer = new JsonSerializer();
 #if TEST_RESPONSES
-            _deserializeSettings.CheckAdditionalContent = true;
-            _deserializeSettings.MissingMemberHandling = MissingMemberHandling.Error;
+            _serializer.CheckAdditionalContent = true;
+            _serializer.MissingMemberHandling = MissingMemberHandling.Error;
 #else
-            _deserializeSettings.CheckAdditionalContent = false;
-            _deserializeSettings.MissingMemberHandling = MissingMemberHandling.Ignore;
+            _serializer.CheckAdditionalContent = false;
+            _serializer.MissingMemberHandling = MissingMemberHandling.Ignore;
 #endif
         }
 
@@ -31,7 +32,8 @@ namespace Discord.Net.Rest
 			if (string.IsNullOrEmpty(json))
 				throw new Exception("API check failed: Response is empty.");
 #endif
-            return JsonConvert.DeserializeObject<T>(json, _deserializeSettings);
+            using (var reader = new JsonTextReader(new StringReader(json)))
+                return (T)_serializer.Deserialize(reader, typeof(T));
         }
     }
 }

src/Discord.Net/Net/WebSockets/GatewaySocket.cs

@@ -7,6 +7,7 @@ using Newtonsoft.Json;
 using Newtonsoft.Json.Linq;
 using System;
 using System.Collections.Generic;
+using System.IO;
 using System.Threading;
 using System.Threading.Tasks;
 
@@ -103,7 +104,11 @@ namespace Discord.Net.WebSockets
         protected override async Task ProcessMessage(string json)
 		{
             base.ProcessMessage(json).GetAwaiter().GetResult(); //This is just a CompletedTask, and we need to avoid asyncs in here
-			var msg = JsonConvert.DeserializeObject<WebSocketMessage>(json);
+
+            WebSocketMessage msg;
+            using (var reader = new JsonTextReader(new StringReader(json)))
+                msg = _serializer.Deserialize(reader, typeof(WebSocketMessage)) as WebSocketMessage;
+            
 			if (msg.Sequence.HasValue)
 				_lastSequence = msg.Sequence.Value;