Node* s = Sequencer(
        b2.opts().WithName("F1_sequencer").WithControlInputs({recv, send}),
        "F1");

    NodeBuilder node_builder("F1", "F1", lib_def.get());
    node_builder.Input(a).Input(b);
    Node* call =
        b2.opts().WithControlInputs({s, b}).FinalizeBuilder(&node_builder);

    Binary(a, call, b2.opts().WithName("G").WithControlInputs({call}));
    TF_EXPECT_OK(b2.ToGraphDef(&graphdef_expected));
  }