const char* path,
                                     TF_ReadOnlyMemoryRegion* region,
                                     TF_Status* status);
int64_t GetFileSize(const TF_Filesystem* filesystem, const char* path,
                    TF_Status* status);
void PathExists(const TF_Filesystem* filesystem, const char* path,
                TF_Status* status);

  Status Stat(const std::string& fname, TransactionToken* token,
              FileStatistics* stat) override;
  Status IsDirectory(const std::string& fname,
                     TransactionToken* token) override;
  Status GetFileSize(const std::string& fname, TransactionToken* token,
                     uint64* file_size) override;
  Status RenameFile(const std::string& src, const std::string& target,
                    TransactionToken* token) override;