Use cacheable instead

src/Discord.Net.WebSocket/DiscordSocketClient.cs

@@ -1464,8 +1464,10 @@ namespace Discord.WebSocket
 
                                     var data = (payload as JToken).ToObject<VoiceServerUpdateEvent>(_serializer);
                                     var guild = State.GetGuild(data.GuildId);
+                                    var cacheable = new Cacheable<IGuild, ulong>(guild, data.GuildId, guild != null,
+                                        async () => (IGuild) await ApiClient.GetGuildAsync(data.GuildId));
 
-                                    var voiceServer = new SocketVoiceServer(data.GuildId, data.Endpoint, data.Token);
+                                    var voiceServer = new SocketVoiceServer(cacheable, data.GuildId, data.Endpoint, data.Token);
                                     await TimedInvokeAsync(_voiceServerUpdatedEvent, nameof(UserVoiceStateUpdated), voiceServer).ConfigureAwait(false);
 
                                     if (guild != null)

src/Discord.Net.WebSocket/SocketVoiceServer.cs

@@ -5,17 +5,17 @@ namespace Discord.WebSocket
     [DebuggerDisplay(@"{DebuggerDisplay,nq}")]
     public class SocketVoiceServer
     {
-        public ulong GuildId { get; private set; }
+        public Cacheable<IGuild, ulong> Guild { get; private set; }
         public string Endpoint { get; private set; }
         public string Token { get; private set; }
 
-        internal SocketVoiceServer(ulong guildId, string endpoint, string token)
+        internal SocketVoiceServer(Cacheable<IGuild, ulong> guild, ulong guildId, string endpoint, string token)
         {
-            GuildId = guildId;
+            Guild = guild;
             Endpoint = endpoint;
             Token = token;
         }
 
-        private string DebuggerDisplay => $"SocketVoiceServer ({GuildId})";
+        private string DebuggerDisplay => $"SocketVoiceServer ({Guild.Id})";
     }
 }