Suggest implementing Gracefully Restart or Shutdown

[3x3y3z3t]

Occasionally during the game, the user will request a Restart or Shutdown, and the OS should honor the request as quickly as possible, otherwise user will rage quit.

Before restarting/shutting down, the OS have to save important data to disk, which may be implemented in two ways:

1. Explicitly switch a process into "save data" mode. The processing should be faster for these processes but IO events appear more frequently.
2. No changes, just keep the same behavior but allow the OS to terminate some processes early to save time slices for processes that carry data.

Each process will now have an extra indicator to tell it is carrying important data or unsaved data. The OS also have an option to terminate a process. When user request a restart/shutdown, the OS may terminate processes that don't hold important data to speed up the process.

Succesfully restarting or shutting down gracefully does not necessarily mean the level is over. The OS will get reboot to a fresh state and the level may continue.

What need to be implemented for this:

• Process can now hold data
• The OS can now choose to terminate a process