[Android] Add setPreferredFramesPerSecond for MapView

[Chaoba]

iOS already added an API to let devs set FPS. It is essential in scenarios cpu load is heavy, so it will be better if we could add one on Android side.

I have tested it by myself, it can change the fps roughly, still need some discussions on it.

[LukasPaczos]

Unfortunately, MapRenderer#updateFps is only responsible for providing a rough FPS count to the end user, as you can see, it is essentially called from the #onDraw and doesn't impact the actual rendering at all. In order to achieve what is proposed, we'd have to either limit core render requests, or ignore them and execute only every other (based on the desired max FPS). The latter might lead to a lot of undesired side effects though.

[LukasPaczos]

Obviously, I'm wrong because you are halting the render thread! Let me give this another look.

[LukasPaczos]

This is an interesting idea @Chaoba, thanks for putting this together.

First of all, the whole logic that is impacting the rendering should be moved out of the updateFps method into onDrawFrame because updateFps is only executed when the onFpsChangedListener is registered, otherwise it's ignored.

Second, I think we can refactor this code to pause the render thread only if we were able to render the last frame faster than the FPS cap allows. Similarly to what you pushed now, but we can base the calcualtions on nanoseconds rather than FPS to limit the amount of divisions that are happening.
In order to achieve that, all we need is to measure the time before the frame, measure the time after the frame (effectively before and after nativeRender call) and check if the delta is smaller than the minimum time required per frame. If it is, we need to sleep for the amount of time needed to fill this gap.

[Chaoba]

@LukasPaczos Thanks for your advise, updated.

[LukasPaczos]

Two notes, otherwise, LGTM!

[tobrun]

thank you for picking up those changes. Two minor comments, will leave the final review to @LukasPaczos

[LukasPaczos]

🚀

Could you squash the commits before merging? Thanks!