resume method Null safety

bool resume()

重新开始监听 Restart listening

Implementation

bool resume() {
  assert(_channel != null, 'You must call setMethodChannel() first');
  if (!_supportPlatform || _channel == null) return false;
  if (_streamSubscription != null && _streamSubscription!.isPaused) {
    _streamSubscription!.resume();
    return true;
  }
  return false;
}