const int64_t* dims, const int num_dims,
                    ForwardOperation* forward_op_) {
  if (num_dims > TensorShape::MaxDimensions()) {
    return errors::InvalidArgument("Value specified for `", attr_name, "` has ",
                                   num_dims,
                                   " dimensions which is over the limit of ",
                                   TensorShape::MaxDimensions(), ".");

            tensorflow::ThreadOptions(), "parallel_device_execute",
            std::bind(&DeviceThread::Run, this))) {}
  ~DeviceThread();

  // Requests that the worker thread execute the specified operation. Blocks
  // until the previously pending operation (a StartExecute without a Join) has
  // finished, if any.
  //
  // `cancellation_manager` must live until after `Join` finishes and pending

// The environment variable that overrides the block size for aligned reads from
// GCS. Specified in MB (e.g. "16" = 16 x 1024 x 1024 = 16777216 bytes).
constexpr char kBlockSize[] = "GCS_READ_CACHE_BLOCK_SIZE_MB";
constexpr size_t kDefaultBlockSize = 64 * 1024 * 1024;
// The environment variable that overrides the max size of the LRU cache of
// blocks read from GCS. Specified in MB.
constexpr char kMaxCacheSize[] = "GCS_READ_CACHE_MAX_SIZE_MB";

  }
  Status SetAttrType(const char* const attr_name, DataType value) override {
    if (!op_) {
      return Status(
          absl::StatusCode::kFailedPrecondition,
          "op_type and op_name must be specified before specifying attrs.");
    }
    op_->node_builder.Attr(attr_name, value);
    return absl::OkStatus();
  }
  Status SetAttrShape(const char* attr_name, const int64_t* dims,