I don't think losing 5s of data is a concern. If we want to make this slightly better we could make GeckoView flush telemetry when it goes to the background (which greatly increases the chance of being killed OOM).
Bug 1570305 Comment 4 Edit History
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I don't think losing 5s of data is a concern. If we want to make this slightly better we could make GeckoView flush telemetry when it goes to the background (which greatly increases the chance of being killed OOM). There is no way on Android to know when your app is killed (android uses `SIG_KILL` or equivalent), this is by design.