Small threading fix, delay to main thread

[rogerbarton]

Previously when calling a function on a worker thread and encountering a load error, setting the pause state would trigger a exception as we use the Unity API on a worker thread.

This is only for Lazy mode, where the thread safety is not yet fully implemented. But it still fixes this issue.

[mcpiroman]

So maybe just extract the dispatching logic to sth like:

void DispatchOnMainThread(Action action)
{
  if(Thread.CurrentThread.ManagedThreadId == _unityMainThreadId)
     action();
  else
     DllManipulatorScript.MainThreadTriggerQueue.Enqueue(action);
}

and use it both here and on previous PR

[rogerbarton]

Yes agreed. However, in the logic of the previous PR there's also an additional bool useMainThreadQueue:

https://github.com/mcpiroman/UnityNativeTool/blob/f4eb21d4089d4a467ac29922c7ea6017228fd0a4/scripts/DllManipulator.cs#L565-L568

I've left it as is in the previous PR (seeing as its only one occurrence) and changed it for these diffs. Or do you see an nice way of doing this?

[mcpiroman]

Yup I forgot about that flag there. You could do something like this but I don't see much sense in doing so

if(useMainThreadQueue)
   DispatchOnMainThread(() => methodInfo.Invoke(null, args));
else
  methodInfo.Invoke(null, args)

so yes, leave this as is, whatever