Copy Aetheria Code

Added a bunch of code from the old Aetheria project

Assets/Scripts/MagicOnion.Unity/ChannelExtensions.cs

@@ -1,19 +0,0 @@
-using Grpc.Core;
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-
-namespace MagicOnion
-{
-    public static class ChannelExtensions
-    {
-        /// <summary>
-        /// Safety way for subscribe streaming events.
-        /// </summary>
-        public static void RegisterStreamingSubscription(this Channel channel, IDisposable subscription)
-        {
-            channel.ShutdownToken.Register(() => subscription.Dispose());
-        }
-    }
-}