I think your last suggestion is dead on - think about the browser event loop where Messages can be triggered all the time from clicks, hovers etc. If you have 4

I think your last suggestion is dead on - think about the browser event loop where Messages can be triggered all the time from clicks, hovers etc. If you have 4 threads and all those threads are pushing Messages then the update thread only has to push the state change notifications and doesn't have to do much blocking of its own