Controlling time using using.

Using.Timepiece.cs

class Program 
{
  static void Main() 
  {
    Tick(); Tick(); Tick();
    DateTime dt = DateTime.Now;
    using (Timepiece.Replacement(() => dt.Add(dt - DateTime.Now))) 
    {
      Tick(); Tick(); Tick();
    }
    Tick(); Tick(); Tick();
  }

  static void Tick() 
  {
    Thread.Sleep(1000);
    Console.WriteLine("The time is {0}", Timepiece.Now.ToLongTimeString());
  }
}

public static class Timepiece 
{
  private static Func<DateTime> _ = () => DateTime.Now;

  public static DateTime Now { get { return _(); } }

  public static IDisposable Replacement(Func<DateTime> f) 
  {
    return new TempTimepiece(f);
  } 

  class TempTimepiece : IDisposable
  {
    private readonly Func<DateTime> _original;

    public TempTimepiece(Func<DateTime> f) 
    {
      _original = _;
      _ = f;
    }
  
    public void Dispose() 
    {
      _ = _original;
    }
  }
}