How can I programmatically suspend a running WorkflowApplication in the middle of execution, not only when idle?

I’m working with a .NET Workflow Foundation (CoreWF) based engine that runs workflows with multiple steps (custom NativeActivity implementations). Each step executes synchronously and immediately schedules the next one, e.g.:

protected override void Execute(NativeActivityContext context)  {
    RunSql("SELECT * FROM Table1");
    WaitForOneMinute();
    context.ScheduleActivity(this.NextStep);
}

So a workflow might look like: SQLStep1 → SQLStep2 → SQLStep3 Each step executes right after the previous one finishes so there are no bookmarks or idle points between them. I need to pause or suspend the workflow in the middle of execution (e.g. during Step 2), possibly because an external user pressed a “Pause” button in the UI. Is it possible to do this from outside the thread that launched the WorkflowApplication ? Probably a new one because it will be triggered from a separate button click.

I thought about maintaining an in-memory dictionary like:

static readonly ConcurrentDictionary<Guid, WorkflowApplication> ActiveInstances = new();

so that when I start a workflow, I can keep a reference and later retrieve it to call Unload(). This works fine while the process is running. However, after an iisreset (or application restart), the dictionary is cleared, meaning I lose all references to the running WorkflowApplication objects.