Fil's Unbelievable Garbage Collector

> The only "pause" threads experience is the callback executed in response to the soft handshake, which does work bounded by that thread's stack height.

So this is probably not great for functional/deeply-recursive code I guess?

Meh.

The stack scan is really fast. There's not a lot of logic in there. If you max out the stack height limit (megabytes of stack?) then maybe that means milliseconds of work to scan that stack. That's still not bad.

That's a very long time. Milliseconds of work is an entire frame update-render cycle in a modern game.