Make DataStore internal and default it to an empty cache.

src/Discord.Net/Data/DataStore.cs

@@ -6,7 +6,7 @@ using System.Linq;
 
 namespace Discord
 {
-    public class DataStore
+    internal class DataStore
     {
         private const int CollectionConcurrencyLevel = 1; //WebSocket updater/event handler. //TODO: Needs profiling, increase to 2?
         private const double AverageChannelsPerGuild = 10.22; //Source: Googie2149

src/Discord.Net/DiscordSocketClient.cs

@@ -73,6 +73,8 @@ namespace Discord
             LargeThreshold = config.LargeThreshold;
             AudioMode = config.AudioMode;
             WebSocketProvider = config.WebSocketProvider;
+
+            DataStore = new DataStore(0, 0);
             _nextAudioId = 1;
 
             _gatewayLogger = LogManager.CreateLogger("Gateway");