dispose method

void dispose()

Close all Streams

Implementation

void dispose() {
  _onDestroy.close();
  _onUrlChanged.close();
  _onStateChanged.close();
  _onProgressChanged.close();
  _onScrollXChanged.close();
  _onScrollYChanged.close();
  _onHttpError.close();
  _onPostMessage.close();
  _instance = null;
}