// subsequent instantiations would return all registered schemes (since the
// vector with the user provided schemes is cleared).
static std::vector<std::string>* GetSchemesFromUserOrEnv() {
  std::vector<std::string>* all_schemes = new std::vector<std::string>;
  tensorflow::Status status =
      tensorflow::Env::Default()->GetRegisteredFileSystemSchemes(all_schemes);

  if (status.ok()) {