Suggestion about waiting of callback in opengl

[mejai1206]

When uses callback with callback-handler, our callback can be returned asynchronously.

On opengl backend, It was confirmed that this is applied using glClientWaitSync. (code)

Sometimes, this method can cause a situation that the result of callback is not guaranteed.

The situation is as follows.

If return status of glClientWaitSync is GL_TIMEOUT_EXPIRED, Filament will retry querying on next frame.

And then the application stop sending frames or exit, we can’t get result of callback.

Even if inefficient, is there a setting that ensures results are always guaranteed?

If not, would it be good to develop a mode that can always guarantee results?
(ex: uses GL_TIMEOUT_IGNORED)