std::string* bucket, std::string* object, TF_Status* status);

namespace tf_random_access_file {
void Cleanup(TF_RandomAccessFile* file);
int64_t Read(const TF_RandomAccessFile* file, uint64_t offset, size_t n,
             char* buffer, TF_Status* status);
}  // namespace tf_random_access_file

namespace tf_writable_file {
void Cleanup(TF_WritableFile* file);

  std::function<uint64_t()> timer_seconds_;

  /// Guards access to the cache and the LRU list.
  absl::Mutex mu_;

  /// The cache (a map from string key to Entry).
  std::map<std::string, Entry> cache_ ABSL_GUARDED_BY(mu_);

  /// The LRU list of entries. The front of the list identifies the most
  /// recently accessed entry.
  std::list<std::string> lru_list_ ABSL_GUARDED_BY(mu_);
};

// setting the same key will lead to errors.
//
// Note that the key-values are only expected to be used for cluster
// configuration data, and should not be used for storing a large amount of data
// or being accessed very frequently.
TF_CAPI_EXPORT extern void TFE_InsertConfigKeyValue(TFE_Context* ctx,
                                                    const char* key,
                                                    const char* value,

  ops->filesystem_ops_api = TF_FILESYSTEM_OPS_API;
  ops->filesystem_ops_size = TF_FILESYSTEM_OPS_SIZE;
  ops->random_access_file_ops_abi = TF_RANDOM_ACCESS_FILE_OPS_ABI;
  ops->random_access_file_ops_api = TF_RANDOM_ACCESS_FILE_OPS_API;
  ops->random_access_file_ops_size = TF_RANDOM_ACCESS_FILE_OPS_SIZE;
  ops->writable_file_ops_abi = TF_WRITABLE_FILE_OPS_ABI;
  ops->writable_file_ops_api = TF_WRITABLE_FILE_OPS_API;

      std::function<void(void*)> plugin_memory_free)
      : filesystem_(std::move(filesystem)),
        ops_(std::move(filesystem_ops)),
        random_access_file_ops_(std::move(random_access_file_ops)),
        writable_file_ops_(std::move(writable_file_ops)),
        read_only_memory_region_ops_(std::move(read_only_memory_region_ops)),
        plugin_memory_allocate_(std::move(plugin_memory_allocate)),

  // device. If is_async=false (constructor argument) this means the ops have
  // run and have results. If is_async=true it means that all of the
  // device-specific executors have scheduled the op.
  //
  // Accepts inferred shapes for outputs (`expected_output_shapes`), which if
  // fully defined will avoid querying the shapes of the underlying
  // TensorHandles when ParallelTensor::Shape is called. This allows async

  ///
  /// Thread safety:
  /// The iterator and timestamp fields should only be accessed while holding
  /// the block-cache-wide mu_ instance variable. The state variable should only
  /// be accessed while holding the Block's mu lock. The data vector should only
  /// be accessed after state == FINISHED, and it should never be modified.
  ///

}

// TODO(agarwal): use an automatic mechanism for handling None arguments to
// gradient functions.
//
// Some gradient functions can accept None arguments for gradients. The
// following maps the operation name to the indices at which the corresponding
// gradient function can accept None values. e.g. FusedBatchNorm outputs 5
// values and hence receives 5 gradient values during backprop. However the

// ---------------------  Coordination service  --------------------------------
// Returns a not owning pointer to the coordination service agent, which is
// opaque to plugin. Plugin OpKernels need to use the accompanying C APIs to
// access coordination service functionalities.
TF_CAPI_EXPORT extern TF_CoordinationServiceAgent*
TF_GetCoordinationServiceAgent(TF_OpKernelContext* ctx);

// Returns true if the coordination service agent has been initialized.