<PackageReference Include="System.Reactive" Version="6.0.0-preview.16" />

System.Reactive.Concurrency.CurrentThreadScheduler

public sealed class CurrentThreadScheduler : LocalScheduler
Represents an object that schedules units of work on the current thread.
namespace System.Reactive.Concurrency { public sealed class CurrentThreadScheduler : LocalScheduler { public static CurrentThreadScheduler Instance { get; } public bool ScheduleRequired { get; } public static bool IsScheduleRequired { get; } } }