Avoid capture AsyncLocal<T>/CallContext.LogicalData to DotNetty's XThread?

[yyjdelete]

That will makes them alive forever and may leak something (but lucky only once per IEventLoopGroup) when used with some other frameworks(an HttpContext in aspnet/aspnetcore for me).

An workaround is add some code to any caller for create DotNetty's IEventLoopGroup in user code like the below.
@nayato Should it be apply directly to XThread, like it does in AbstractSocketByteChannel and SocketDatagramChannel? But one problem is the api is only available for netfx and netstandard2.0, so not available for all netcoreapp1.x, and 2.x before directly support for netstandard2.0 is added.

        void CreateLongRunningTask(XParameterizedThreadStart threadStartFunc)
        {
#if NETSTANDARD1_3
            CreateLongRunningTaskUnsafe(threadStartFunc);
#else//NET45 || NETSTANDARD2_0
            if (ExecutionContext.IsFlowSuppressed())
            {
                CreateLongRunningTaskUnsafe(threadStartFunc);
            }
            else
            {
                using (ExecutionContext.SuppressFlow())
                {
                    CreateLongRunningTaskUnsafe(threadStartFunc);
                }
            }
#endif
        }

Test code: an edited version of Echo.Server.

        static async Task RunServerAsync()
        {
            IEventLoopGroup bossGroup;
            IEventLoopGroup workerGroup;

#if NET451
            System.Runtime.Remoting.Messaging.CallContext.LogicalSetData("test001", new { B = 1 });
#else//netcoreapp1.1
            var local = new System.Threading.AsyncLocal<object>();
            local.Value = new { C = 1 };
#endif
            if (ServerSettings.UseLibuv)
            {
                var dispatcher = new DispatcherEventLoopGroup();
                bossGroup = dispatcher;
                workerGroup = new WorkerEventLoopGroup(dispatcher);
            }
            else
            {
                bossGroup = new MultithreadEventLoopGroup(1);
                workerGroup = new MultithreadEventLoopGroup();
            }

#if NET451
            System.Runtime.Remoting.Messaging.CallContext.FreeNamedDataSlot("test001");
            Console.WriteLine("LogicalData(out dotnetty): " + System.Runtime.Remoting.Messaging.CallContext.LogicalGetData("test001"));
#else//netcoreapp1.1
            local.Value = null;
            Console.WriteLine("AsyncLocal(out dotnetty): " + local.Value);
#endif
            bossGroup.GetNext().Execute(() =>
            {
#if NET451
                Console.WriteLine("LogicalData(in dotnetty's boss): " + System.Runtime.Remoting.Messaging.CallContext.LogicalGetData("test001"));
#else//netcoreapp1.1
                Console.WriteLine("AsyncLocal(in dotnetty's boss): " + local.Value);
#endif
            });
            workerGroup.GetNext().Execute(() =>
            {
#if NET451
                Console.WriteLine("LogicalData(in dotnetty's worker): " + System.Runtime.Remoting.Messaging.CallContext.LogicalGetData("test001"));
#else//netcoreapp1.1
                Console.WriteLine("AsyncLocal(in dotnetty's worker): " + local.Value);
#endif
            });
            Console.ReadLine();
        }

        static void Main() => RunServerAsync().Wait();