addStream method
Adds a stream of byte chunks to the request body.
Each chunk is forwarded to the internal stream controller and the underlying request.
Implementation
@override
Future<void> addStream(Stream<List<int>> stream) {
// Broadcast the incoming stream so multiple listeners can subscribe.
final newStream = stream.asBroadcastStream();
// Listen and add each chunk to the internal stream controller.
newStream.listen((chunk) => _streamController.add(chunk));
// Forward the stream to the actual request.
return request.addStream(newStream);
}