for (const auto* input_edge : in_edges) {
    const Node& input_node = *input_edge->src();
    if (input_node.IsSource()) {
      if (in_edges.size() != 1) {
        return errors::FailedPrecondition(
            "The node has other inputs besides the _Source node");
      }
      // We don't import the _SOURCE node.
      continue;
    }
    if (input_node.IsArg() && input_edge->IsControlEdge()) {

  }
  if (!ret_node) {
    return errors::Internal("No _Retval node for loop cond function ",
                            loop_cond_func->name());
  }
  Node* loop_cond;
  TF_RETURN_IF_ERROR(ret_node->input_node(0, &loop_cond));

  // Build the XlaSendToHost node.
  NodeDefBuilder send_loop_cond_builder(
      absl::StrCat("send_oc_while_cond_", while_node->name()), "XlaSendToHost");