Is there someting like Dispatcher.CheckAccess() when using Scheduler - system.reactive

Question

I want to do the equivalent of:
if (dispatcher.CheckAccess())
{
// invoke synchronously if we are on the dispatcher thread
collectionChangedEventHandler(this, args);
}
else
{
dispatcher.BeginInvoke(new Action(() => collectionChangedEventHandler(this, args)));
}
I have not found a way to do this using an IScheduler.
Pseudo code for what I want:
if (scheduler.CheckAccess())
{
collectionChangeEventHandler(sender, args);
}
else
{
scheduler.Schedule(() => collectionChangeEventHandler(sender, args));
}
There is CurrentThreadScheduler.ScheduleRequired that looks promising but the documentation is sparse.

Answer 1

No, but you can write your own CheckAccessDispatcherScheduler that decorates DispatcherScheduler.
https://github.com/Reactive-Extensions/Rx.NET/blob/master/Rx.NET/Source/System.Reactive.Windows.Threading/Reactive/Concurrency/DispatcherScheduler.cs
class CheckAccessDispatcherScheduler : LocalScheduler, ISchedulerPeriodic
{
...
public override IDisposable Schedule<TState>(TState state, Func<IScheduler, TState, IDisposable> action)
{
if (decoratedDispatcher.Dispatcher.CheckAccess())
{
action(this, state, Disposable.Empty);
return Disposable.Empty;
}
else
{
return decoratedDispatcher.Schedule(state, action);
}
}
...
}