NodaTime Static Clock

NodaClock.cs

public static class NodaClock
{
    private static readonly AsyncLocal<IClock> ClockThreadSafe;

    public static void ChangeClock(IClock clock)
    {
        ClockThreadSafe.Value = clock;
    }

    static ApiClock()
    {
        ClockThreadSafe = new AsyncLocal<IClock>();
    }

    public static IClock Clock => ClockThreadSafe.Value ?? SystemClock.Instance;

    public static Instant Now => Clock.GetCurrentInstant();
}

OverrideNodaClock.cs

public class OverrideNodaClock : IDisposable
{
    private OverrideNodaClock(FakeClock fakeClock)
    {
        _fakeClock = fakeClock;
        _clock = NodaClock.Clock;

        NodaClock.ChangeClock(_fakeClock);
    }

    public OverrideApiClock(Instant instant)
        : this(new FakeClock(instant))
    {
    }

    public void Dispose()
    {
        ApiClock.ChangeClock(_clock);
    }

    public OverrideApiClock Reset(Instant instant)
    {
        _fakeClock.Reset(instant);
        return this;
    }

    public OverrideApiClock Advance(Duration duration)
    {
        _fakeClock.Advance(duration);
        return this;
    }

    private readonly IClock _clock;
    private readonly FakeClock _fakeClock;

}