close method Null safety
Implementation
Future<void> close() async {
var futures = <Future<void>>[];
if (_content is InputStreamBase) {
futures.add((_content as InputStreamBase).close());
}
if (_rawContent is InputStreamBase) {
futures.add((_rawContent as InputStreamBase).close());
}
_content = null;
_rawContent = null;
await Future.wait(futures);
}