//
  // WARNING: The destructor of this class is marked as protected to disallow
  // clients from directly destroying this object since it may manage it's own
  // lifetime through ref counting. Thus this must be allocated on the heap and
  // clients MUST call Release() in order to destroy an instance of this class.
  virtual void Release() = 0;

  virtual Status Reset(const char* op, const char* raw_device_name) = 0;

 private:
  struct Entry {
    /// The timestamp (seconds) at which the entry was added to the cache.
    uint64_t timestamp;

    /// The entry's value.
    T value;

    /// A list iterator pointing to the entry's position in the LRU list.
    std::list<std::string>::iterator lru_iterator;
  };

  bool LookupLocked(const std::string& key, T* value)
      ABSL_EXCLUSIVE_LOCKS_REQUIRED(mu_) {

The top-level scripts and utility scripts should be fairly well-documented. Here
is a brief explanation of how they tie together:

1.  `envs/*` are lists of variables made with bash syntax. A user must set a
    `TFCI` env param pointing to a list of `env` files.
2.  `utilities/setup.sh`, initialized by all top-level scripts, reads and sets
    values from those `TFCI` paths.
    -   `set -a` / `set -o allexport` exports the variables from `env` files so

// maximum number of in flight async nodes. Enqueuing of additional async ops
// after the limit is reached blocks until some inflight nodes finishes.
// The effect is bounding the memory held by inflight TensorHandles that are
// referenced by the inflight nodes.
// A recommended value has not been established.
// A value of 0 removes the limit, which is the behavior of TensorFlow 2.11.

  /// mu_.
  struct Block {
    /// The block data.
    std::vector<char> data;
    /// A list iterator pointing to the block's position in the LRU list.
    std::list<Key>::iterator lru_iterator;
    /// A list iterator pointing to the block's position in the LRA list.
    std::list<Key>::iterator lra_iterator;
    /// The timestamp (seconds since epoch) at which the block was cached.

namespace tensorflow {

// Checks that all schemes provided by a plugin are valid.
// TODO(b/139060984): More validation could be done here, based on supported
// charset, maximum length, etc. Punting it for later.
static Status ValidateScheme(const char* scheme) {
  if (scheme == nullptr)
    return errors::InvalidArgument(
        "Attempted to register filesystem with `nullptr` URI scheme");
  return OkStatus();
}

*   `tf.image`:
    *   Adds deterministic `tf.image.stateless_random_*` functions for each
        `tf.image.random_*` function. Added a new op
        `stateless_sample_distorted_bounding_box` which is a deterministic
        version of `sample_distorted_bounding_box` op. Given the same seed,
        these stateless functions/ops produce the same results independent of
        how many times the function is called, and independent of global seed

  //
  // WARNING: The destructor of this class is marked as protected to disallow
  // clients from directly destroying this object since it may manage its own
  // lifetime through ref counting. Thus clients MUST call Release() in order to
  // destroy an instance of this class.
  virtual void Release() = 0;

  // Creates an operation builder and ties it to this context.

  // AssignSub, ...).
  void GeneralAssignment(const char* op_name, TFE_Context* context,
                         TFE_TensorHandle* value, TF_Status* status);

  // The a handle for the resource-dtype tensor pointing to the variable's
  // buffer.
  TFE_TensorHandle* handle_;
  // The dtype of the variable's buffer (input dtype for assignments, output
  // dtype of read operations).
  TF_DataType type_;
};

    TF_OperationDescription* desc, TF_Status* status);

// If this function succeeds:
//   * *status is set to an OK value,
//   * a TF_Operation is added to the graph,
//   * a non-null value pointing to the added operation is returned --
//     this value is valid until the underlying graph is deleted.
// Otherwise:
//   * *status is set to a non-OK value,
//   * the graph is not modified,