dispose method

Implementation

void dispose() {
  unawaited(_updatesSubscription?.cancel());
  unawaited(_recordsSubscription?.cancel());
  for (var subscription in _watches.values) {
    unawaited(subscription.cancel());
  }
  _watches.clear();
  _changesTimer?.cancel();
  _changesTimer = null;
  unawaited(_coalescedTicks.close());
  _panel = null;
}