C# - Task.Start 메서드 호출 시 "System.InvalidOperationException: 'Start may not be called on a task that has completed.'" 예외 발생

이 글은 다음의 질문에 대한 답변입니다.

[WPF] Task 관련 질문 드립니다.
; https://www.sysnet.pe.kr/3/0/5429

[WPF] Task 관련 재질문 드립니다.
; https://www.sysnet.pe.kr/3/0/5430

using System;
using System.Threading;
using System.Threading.Tasks;
using System.Windows;

namespace WpfApp1
{
    public partial class MainWindow : Window
    {
        private CancellationTokenSource _cancelTask = new CancellationTokenSource();

        public MainWindow()
        {
            InitializeComponent();
        }

        Task _task;

        private void Connect_Click(object sender, RoutedEventArgs e)
        {
            _task = new Task((Action)myAction, _cancelTask.Token);
            _task.Start();
        }

        private void myAction()
        {
        }

        private void Disconnect_Click(object sender, RoutedEventArgs e)
        {
            _cancelTask.Cancel();
        }
    }
}

System.InvalidOperationException
  HResult=0x80131509
  Message=Start may not be called on a task that has completed.
  Source=mscorlib
  StackTrace:
   at System.Threading.Tasks.Task.Start(TaskScheduler scheduler) in f:\dd\ndp\clr\src\BCL\system\threading\Tasks\Task.cs:line 1105
   at WpfApp1.MainWindow.Connect_Click(Object sender, RoutedEventArgs e) in C:\temp\WpfApp1\WpfApp1\MainWindow.xaml.cs:line 22
   at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
...[생략]...
   at System.Windows.Application.RunDispatcher(Object ignore)
   at System.Windows.Application.RunInternal(Window window)
   at WpfApp1.App.Main()

  This exception was originally thrown at this call stack:
    System.Threading.Tasks.Task.Start(System.Threading.Tasks.TaskScheduler) in Task.cs
    WpfApp1.MainWindow.Connect_Click(object, System.Windows.RoutedEventArgs) in MainWindow.xaml.cs
...[생략]...
    System.Windows.EventRoute.InvokeHandlersImpl(object, System.Windows.RoutedEventArgs, bool)
    ...
    [Call Stack Truncated]

private void Connect_Click(object sender, RoutedEventArgs e)
{
    _cancelTask = new CancellationTokenSource();
    _task = new Task((Action)myAction, _cancelTask.Token);
    _task.Start();
}