Method Tell

cpp/src/arrow/filesystem/gcsfs.cc:260–263

    return stream_->Abort();
  }
  Result<int64_t> Tell() const override {
    ARROW_RETURN_NOT_OK(InitializeStream());
    return stream_->TellOr(metadata_.size());
  }
  bool closed() const override {
    auto status = InitializeStream();
    if (!status.ok()) return true;