Added RPC channel and guild entities, Get and Select methods

src/Discord.Net.Rpc/API/Rpc/ExtendedVoiceState.cs

@@ -0,0 +1,21 @@
+#pragma warning disable CS1591
+using Newtonsoft.Json;
+
+namespace Discord.API.Rpc
+{
+    public class ExtendedVoiceState
+    {
+        [JsonProperty("user")]
+        public User User { get; set; }
+        [JsonProperty("voice_state")]
+        public Optional<VoiceState> VoiceState { get; set; }
+        [JsonProperty("nick")]
+        public Optional<string> Nickname { get; set; }
+        [JsonProperty("volume")]
+        public Optional<int> Volume { get; set; }
+        [JsonProperty("mute")]
+        public Optional<bool> Mute { get; set; }
+        [JsonProperty("pan")]
+        public Optional<Pan> Pan { get; set; }
+    }
+}