for (int i = start; i <= end; i++) {
QVariant variant = parent.model()->index(i, 0, parent).data(NetworkModel::BufferIdRole);
if (!variant.isValid())
for (int i = start; i <= end; i++) {
QVariant variant = parent.model()->index(i, 0, parent).data(NetworkModel::BufferIdRole);
if (!variant.isValid())