问题 了解TaskScheduler.Current的行为

这是一个简单的WinForms应用程序：

using System;
using System.Diagnostics;
using System.Threading;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WindowsFormsApplication
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private async void button1_Click(object sender, EventArgs e)
        {
            var ts = TaskScheduler.FromCurrentSynchronizationContext();
            await Task.Factory.StartNew(async () =>
            {
                Debug.WriteLine(new
                {
                    where = "1) before await",
                    currentTs = TaskScheduler.Current,
                    thread = Thread.CurrentThread.ManagedThreadId,
                    context = SynchronizationContext.Current
                });

                await Task.Yield(); // or await Task.Delay(1)

                Debug.WriteLine(new
                {
                    where = "2) after await",
                    currentTs = TaskScheduler.Current,
                    thread = Thread.CurrentThread.ManagedThreadId,
                    context = SynchronizationContext.Current
                });

            }, CancellationToken.None, TaskCreationOptions.None, scheduler: ts).Unwrap();
        }
    }
}

调试输出（单击按钮时）：

{where = 1}在await之前，currentTs = System.Threading.Tasks.SynchronizationContextTaskScheduler，thread = 9，context = System.Windows.Forms.WindowsFormsSynchronizationContext}
{where = 2}等待之后，currentTs = System.Threading.Tasks.ThreadPoolTask​​Scheduler，thread = 9，context = System.Windows.Forms.WindowsFormsSynchronizationContext}

问题是： 为什么是 TaskScheduler.Current 改变 SynchronizationContextTaskScheduler 至 ThreadPoolTaskScheduler 后 await 这里？

这基本上表现出这种行为 TaskCreationOptions.HideScheduler 对于 await 在我看来，延续，这是意想不到的和不可取的。

这个问题是由我的另一个问题引发的：

AspNetSynchronizationContext并等待ASP.NET中的延续。