Data requests when app is backgrounded

[tobrun]

Users have reported seeing data requests occurring when the app has been backgrounded (the Activity is in an paused state). One example given was the download of a sprite (eg. sprite@2x.png) which occured when the app has been backgrounded for a couple of hours. Ideally we stop requesting resources when onPause occurs and only resume downloads when we hit onResume.

[kkaefer]

It's likely that this happens because resources expire while the app is still running in the background. When a resource expires, we try to reload/refresh it.

[kkaefer]

@tobrun DefaultFileSource has the ability to pause:

mapbox-gl-native/include/mbgl/storage/default_file_source.hpp

Lines 126 to 140 in 8e01f52

	/*
	* Pause file request activity.
	*
	* If pause is called then no revalidation or network request activity
	* will occur.
	*/
	void pause();
	/*
	* Resume file request activity.
	*
	* Calling resume will unpause the file source and process any tasks that
	* expired while the file source was paused.
	*/
	void resume();

Are we calling this when the app goes to the background?

[tobrun]

Thank you for 👀 @kkaefer, we aren't atm, will fix this up.

[tobrun]

This landed in 5.2.0