/// the same key.
  void Insert(const std::string& key, const T& value) {
    if (max_age_ == 0) {
      return;
    }
    absl::MutexLock lock(&mu_);
    InsertLocked(key, value);
  }

  // Delete the entry with key `key`. Return true if the entry was found for
  // `key`, false if the entry was not found. In both cases, there is no entry
  // with key `key` existed after the call.

// returned and both error counters are set to zero.
//
// Otherwise, while traversing the tree, undeleted_file_count and
// undeleted_dir_count are updated if an entry of the corresponding type could
// not be deleted. The returned error status represents the reason that any one
// of these entries could not be deleted.
//
// Typical status codes:

int TransferFileContents(const char* src, const char* dst, mode_t mode,
                         off_t size);

// Returns true only if `entry` points to an entry other than `.` or `..`.
//
// This is a filter for `scandir`.
int RemoveSpecialDirectoryEntries(const struct dirent* entry);

}  // namespace tf_posix_filesystem

  // Returns a map from variable names to their shapes.  Slices of a partitioned
  // tensor are combined into a single entry.
  const TensorSliceReader::VarToShapeMap& GetVariableToShapeMap() const;

  // Returns a map from variable names to their data types.  Slices of a
  // partitioned tensor are combined into a single entry.
  const TensorSliceReader::VarToDataTypeMap& GetVariableToDataTypeMap() const;