namespace System.Reactive.Concurrency { public sealed class ThreadPoolScheduler : LocalScheduler, ISchedulerLongRunning, ISchedulerPeriodic { public static ThreadPoolScheduler Instance { get; } public IDisposable ScheduleLongRunning<[Nullable(2)] TState>(TState state, Action<TState, ICancelable> action); public IDisposable SchedulePeriodic<[Nullable(2)] TState>(TState state, TimeSpan period, Func<TState, TState> action); } }