TF_Operation* oper, const char* attr_name, TF_Buffer* output_attr_value,
    TF_Status* status);

// Get the number of attributes the operation has.
TF_CAPI_EXPORT extern int TF_OperationGetNumAttrs(TF_Operation* oper);

// Get the length of the name of the ith attribute, or -1 if there is not an
// ith attribute.
TF_CAPI_EXPORT extern int TF_OperationGetAttrNameLength(TF_Operation* oper,

  auto oper = TF_FinishOperation(desc, s_);
  ASSERT_EQ(TF_OK, TF_GetCode(s_)) << TF_Message(s_);
  EXPECT_TF_META("v", -1, TF_ATTR_STRING, 5);

  ASSERT_EQ(1, TF_OperationGetNumAttrs(oper));
  ASSERT_EQ(1, TF_OperationGetAttrNameLength(oper, 0));

  std::unique_ptr<char[]> value(new char[1]);

  TF_OperationGetAttrName(oper, 0, value.get(), s_);