opts.prefix = prefix;

  for (int i = 0; i < dst_inputs.size(); ++i) {
    opts.input_map[ToTensorId(src_inputs[i])] =
        TensorId(dst_inputs[i].node()->name(), dst_inputs[i].index());
  }
  opts.skip_mapped_nodes = true;

  for (const tensorflow::Operation& op : control_deps) {
    opts.control_dependencies.push_back(op.node()->name());
  }

  for (int i = 0; i < nreturn_nodes; ++i) {

    const auto& data = block->data;
    if (offset >= pos + data.size()) {
      // The requested offset is at or beyond the end of the file. This can
      // happen if `offset` is not block-aligned, and the read returns the last
      // block in the file, which does not extend all the way out to `offset`.
      std::stringstream os;

      // and hence expect the input to be forwarded to the return tensor.
      EXPECT_EQ(orig_ptr, TF_TensorData(t));
    } else {
      // In sync mode, forwarding can't really happen since the client code will
      // have a reference count on the input tensor while the kernel is being
      // executed and thus it cannot be re-used for the return tensor.
      EXPECT_NE(orig_ptr, TF_TensorData(t));