// If 'reuse_existing_functions' is set, use an existing function with the
  // same name, if any.
  // If 'rewrite_subgraph_fn' is set, it is applied to each subgraph before
  // function conversion.
  Status BuildFunctionDefs(const RewriteSubgraphFn& rewrite_subgraph_fn,
                           bool reuse_existing_functions,
                           FunctionLibraryDefinition* library);

    RewriteSubgraphFn;

// Transformation that finds subgraphs whose nodes are marked with
// 'group_attribute', splits those subgraphs into functions, and replaces
// the originals with function calls.
//
// 'group_attribute' must be a string valued-attribute that names the new
// functions to introduce.
//
// If 'rewrite_subgraph_fn' is set, it is applied to each subgraph before

  auto flr = pflr->GetFLR("/job:localhost/replica:0/task:0/cpu:0");

  std::unique_ptr<Graph> graph_out;
  s = EncapsulateSubgraphsInFunctions("_encapsulate", *graph,
                                      /*rewrite_subgraph_fn=*/{},
                                      /*reuse_existing_functions=*/false,
                                      &graph_out, lib_def.get());
  if (!s.ok()) return s;