It would be nice to have a "dataflow" debugger tool in the xap editor to visualize the current dataflow queue and be able to step, one-by-one, through each event. So, for example, you might have a couple `data in` events in the queue. You step through one of them, look at the state of the system, click a button to step through the next one, look at the system, &c...
It would definitely be helpful with debugging loops.
Thanks for sharing this thought!