Simulator compatibility

[niclashoyer]

Is there a list of possible differences / caveats when using the simulator?

I'm currently investigating a nasty problem while hacking on #106 where I thought this might be a deep sleep issue. But then I found out that EVENT_LOW_ENERGY_UPDATE is never fired. My current guess is, that the simulator might not work properly when not in focus (background tab in browser).

I think that the simulation is stopped or runs much slower when the tab is not in focus. At least the EVENT_TICK is not fired properly and the timestamps are off. It also misses this comparison in the check for scheduled tasks, so that the EVENT_BACKGROUND_TASK is never fired.

If the simulator stays on screen / in focus all the time, this does not happen.

[yasuiniko]

Even when the simulator is in focus, it becomes unresponsive for me after le_mode_ticks runs out (roughly speaking; I have never debugged C before and have not attempted it yet). I have only tested with 5 seconds of movement_le_inactivity_deadlines and alarm_time.unit.second = 3. I tried safari and firefox, with the same behaviour.