<PackageReference Include="System.Reactive" Version="6.0.1-preview.1" />

System.Reactive.PlatformServices.PeriodicTimerSystemClockMonitor

public class PeriodicTimerSystemClockMonitor : INotifySystemClockChanged
(Infrastructure) Monitors for system clock changes based on a periodic timer.
public event EventHandler<SystemClockChangedEventArgs> SystemClockChanged

Event that gets raised when a system clock change is detected.

public PeriodicTimerSystemClockMonitor(TimeSpan period)

Creates a new monitor for system clock changes with the specified polling frequency.