public DispatcherState([NotNull] IDispatcherService dispatcher)
{
if (dispatcher == null)
{
throw new ArgumentNullException(nameof(dispatcher));
}
if (dispatcher.CheckAccess())
{
throw new InvalidOperationException("A dispatcher lock must be created from a different thread that the dispatchers it should lock");
}
Dispatcher = dispatcher;
Locked = new TaskCompletionSource <int>();
Unlocked = new TaskCompletionSource <int>();
}