add method
Adds data
to the sink.
Must not be called after a call to close.
Implementation
@override
void add(List<int> data) {
_stream.write(Uint8List.fromList(data));
// Note: P2PStream.write is often async. If writeDelimitedMessage expects synchronous writes
// or needs flow control, this adapter might need to be more complex (e.g., using a StreamController).
// For now, assuming P2PStream.write handles buffering or is suitably async.
}