backdateSessionStart static method
Moves the session start by into the past. Past sessionMaxDuration,
the next launch starts a new session.
Implementation
static Future<void> backdateSessionStart(Duration by) async {
final storage = await _storage();
storage.setItem(
SessionKeys.startTime,
'${msToNs(systemClock() - by.inMilliseconds)}',
);
await storage.flushWrites();
}