using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Xml.Serialization;

using System.Xml;

using System.IO;

using System.Diagnostics;

using System.Collections.ObjectModel;

using System.Threading;

using System.ComponentModel;

using System.Xml.Linq;

using System.Reflection;

using System.Data;

using System.Xml.Schema;

using System.Text.RegularExpressions;

using System.Net;

using System.Xml.XPath;

using System.Globalization;

using System.ComponentModel.DataAnnotations;

using System.Collections;

using System.Runtime.InteropServices;

using System.Runtime.Serialization;

using System.Threading.Tasks;

​

// https://stackoverflow.com/questions/48350114/saving-xelement-asynchronously

​

    public static class XElementExtensions

    {

        public static async Task WriteToAsync(this XContainer element, Stream stream, bool defAttr = true, bool indent = false)

        {

            var settings = new XmlWriterSettings

            {

                Async = true,

                CloseOutput = false,

                Indent = indent,

            };          

            using (var writer = XmlWriter.Create(stream, settings))

            using (var reader = element.CreateReader())

            {

                await writer.WriteNodeAsync(reader, defAttr);

            }

        }

    }

​

    class TestClass

    {

        public static async Task TestAsync(XContainer element, Stream stream)

        {

            await element.WriteToAsync(stream, false, true);

        }

        static void Test(XContainer element)

        {

            Console.WriteLine("\nTesting {0}", element.GetType());

            using (var stream = new MemoryStream())

            {

                var task = TestAsync(element, stream);

                Task.WaitAll(task);

                stream.Position = 0L;

                Console.WriteLine(new StreamReader(stream).ReadToEnd());

            }

        }

        public static void Test()

        {

            var document = XDocument.Parse(GetXml());

​

            Test(document);

​

            Test(document.Root);            

        }

        static string GetXml()

        {

            var xml = @"<?xml version=""1.0"" encoding=""utf-8""?>

<TraitContainer>

  <Traits>

    <Trait>

      <name>Frail</name>

      <description>I, for one, was never strong.</description>

      <traitID>1</traitID>

      <pathToIcon>SomeIconPath</pathToIcon>

      <vMods>

        <VitalModifier>

          <modifier>-1</modifier>

          <type>Health</type>

        </VitalModifier>

        <VitalModifier>

          <modifier>-1</modifier>

          <type>Sanity</type>

        </VitalModifier>

      </vMods>

      <pMods>

        <ProficiencyModifier>

          <modifier>1</modifier>

          <type>Hacking</type>

        </ProficiencyModifier>

      </pMods>

    </Trait>

<!-- Fixed added missing Traits end element: -->

  </Traits>

  </TraitContainer>";

            return xml;

        }

    }

​

    public class AssertionFailedException : System.Exception

    {

        public AssertionFailedException() : base() { }

​

        public AssertionFailedException(string s) : base(s) { }

    }

​

    public static class Assert

    {

        public static void IsTrue(bool value)

        {

            IsTrue(value, "failed");

        }

​

        public static void IsTrue(bool value, string message)

        {

            if (value == false)

                throw new AssertionFailedException(message ?? "failed");

        }

    }

    public class Program

    {

        public static void Main()

        {

            Console.WriteLine("Roslyn 2.0 Compiler; Environment version: " + Environment.Version);

            Console.WriteLine();

​

            try

            {

                TestClass.Test();

            }

            catch (Exception ex)

            {

                Console.WriteLine("Uncaught exception: ");

                Console.WriteLine(ex);

                throw;

            }

        }

    }

​