TF_Input feed_port;
  EXPECT_EQ(1, TF_OperationOutputConsumers(TF_Output{feed, 0}, &feed_port, 1));
  EXPECT_EQ(add, feed_port.oper);
  EXPECT_EQ(0, feed_port.index);

  // The scalar const oper also has a consumer.
  ASSERT_EQ(1, TF_OperationOutputNumConsumers(TF_Output{three, 0}));
  TF_Input three_port;
  EXPECT_EQ(1,
            TF_OperationOutputConsumers(TF_Output{three, 0}, &three_port, 1));

// modification of the graph can increase the number of consumers of
// an operation.  Returns the number of output consumers (should match
// TF_OperationOutputNumConsumers(oper_out)).
TF_CAPI_EXPORT extern int TF_OperationOutputConsumers(TF_Output oper_out,
                                                      TF_Input* consumers,
                                                      int max_consumers);