buffer.SetData (data_copy.data(), data_copy.size());
buffer.Size (j->data.size());
r = writer.WriteAncillaryResource (buffer, enc.context(), enc.hmac());
buffer.SetData (data_copy.data(), data_copy.size());
buffer.Size (j->data.size());
r = writer.WriteAncillaryResource (buffer, enc.context(), enc.hmac());