Created events for when a user joins or leaves a voice channel

src/Discord.Net/DiscordClient.Events.cs

@@ -27,7 +27,13 @@ namespace Discord
         public event EventHandler<UserEventArgs> UserBanned = delegate { };
         public event EventHandler<ChannelUserEventArgs> UserIsTyping = delegate { };
         public event EventHandler<UserEventArgs> UserJoined = delegate { };
+        /// <summary>When a user joins a voice channel.
+        /// Discord API Event name: VOICE_STATE_UPDATE.</summary>
+        public event EventHandler<ChannelUserEventArgs> UserJoinedVoiceChannel = delegate { };
         public event EventHandler<UserEventArgs> UserLeft = delegate { };
+        /// <summary>When a user leaves a voice channel.
+        /// Discord API Event name: VOICE_STATE_UPDATE.</summary>
+        public event EventHandler<ChannelUserEventArgs> UserLeftVoiceChannel = delegate { };
         public event EventHandler<UserUpdatedEventArgs> UserUpdated = delegate { };
         public event EventHandler<UserEventArgs> UserUnbanned = delegate { };
 
@@ -81,8 +87,12 @@ namespace Discord
             => OnEvent(UserIsTyping, new ChannelUserEventArgs(channel, user));
         private void OnUserJoined(User user)
             => OnEvent(UserJoined, new UserEventArgs(user));
+        private void OnUserJoinedVoiceChannel(Channel channel, User user)
+            => OnEvent(UserJoinedVoiceChannel, new ChannelUserEventArgs(channel, user));
         private void OnUserLeft(User user)
             => OnEvent(UserLeft, new UserEventArgs(user));
+        private void OnUserLeftVoiceChannel(Channel channel, User user)
+            => OnEvent(UserLeftVoiceChannel, new ChannelUserEventArgs(channel, user));
         private void OnUserUnbanned(User user)
             => OnEvent(UserUnbanned, new UserEventArgs(user));
         private void OnUserUpdated(User before, User after)

src/Discord.Net/DiscordClient.cs

@@ -981,6 +981,20 @@ namespace Discord
                                     user.Update(data);
                                     //Logger.Verbose($"Voice Updated: {server.Name}/{user.Name}");
                                     OnUserUpdated(before, user);
+
+                                    if (before.VoiceChannel != user.VoiceChannel)
+                                    {
+                                        if (before.VoiceChannel != null)
+                                        {
+                                            Logger.Verbose($"USER_LEFT_VOICE_CHANNEL: {user.Path} left voice channel {before.VoiceChannel.Path}");
+                                            OnUserLeftVoiceChannel(before.VoiceChannel, user);
+                                        }
+                                        if (user.VoiceChannel != null)
+                                        {
+                                            Logger.Verbose($"USER_JOINED_VOICE_CHANNEL: {user.Path} joined voice channel {user.VoiceChannel.Path}");
+                                            OnUserJoinedVoiceChannel(user.VoiceChannel, user);
+                                        }
+                                    }
                                 }
                                 /*else //Occurs when a user leaves a server
                                     Logger.Warning("VOICE_STATE_UPDATE referenced an unknown user.");*/