flush method

@override Future<void> flush()

Flushes any buffered output.

Implementation

@override
Future<void> flush() {
  final existing = _flushInFlight;
  if (existing != null) return existing;

  final f = _flushAll();
  _flushInFlight = f.whenComplete(() {
    _flushInFlight = null;
  });
  return _flushInFlight!;
}