namespace System.Reactive.PlatformServices { public static class HostLifecycleService { public static event EventHandler<HostSuspendingEventArgs> Suspending; public static event EventHandler<HostResumingEventArgs> Resuming; public static void AddRef(); public static void Release(); } } namespace System.Reactive.PlatformServices { public interface INotifySystemClockChanged { event EventHandler<SystemClockChangedEventArgs> SystemClockChanged; } }