kikuchan
Some joysticks with high sampling rate need to be read() more fast,
otherwise it delay user inputs due to internal queue.
Especially, an app that issues SDL_PollEvent() not so frequent
If the app is in landscape mode and the user presses the power button, a pause
is followed immediately by a surfaceChanged event because the lock screen
is shown in portrait mode. This triggers a "false" resume.
So, we just pause and resume following the onWindowFocusChanged events.
Also, wait for SDL_APP_WILLENTERBACKGROUND and SDL_APP_DIDENTERBACKGROUND before
blocking the event pump.