// must define.
typedef void (*TFInitGraphPluginFn)(TP_OptimizerRegistrationParams* const,
                                    TF_Status* const);

// Registers Graph optimizers.
Status InitGraphPlugin(void* dso_handle);

// Allow registering a graph optimizer using a function (used for
// testing).
Status InitGraphPlugin(TFInitGraphPluginFn init_fn);

struct GrapplerItem;
class Cluster;

      env->GetSymbolFromLibrary(dso_handle, "TF_InitGraph", &dso_symbol));

  // Step 2: Call `TF_InitPlugin`
  auto init_fn = reinterpret_cast<TFInitGraphPluginFn>(dso_symbol);
  return InitGraphPlugin(init_fn);
}

absl::Status InitGraphPlugin(TFInitGraphPluginFn init_fn) {
  TP_OptimizerRegistrationParams params{
      TP_OPTIMIZER_REGISTRATION_PARAMS_STRUCT_SIZE};
  TP_Optimizer optimizer{TP_OPTIMIZER_STRUCT_SIZE};