Method ListBucketsAsync

cpp/src/arrow/filesystem/s3fs.cc:3033–3040

  }

  Future<std::vector<std::string>> ListBucketsAsync() {
    auto deferred =
        [self = shared_from_this()]() mutable -> Result<std::vector<std::string>> {
      ARROW_ASSIGN_OR_RAISE(auto client_lock, self->holder_->Lock());
      return self->ProcessListBuckets(client_lock.Move()->ListBuckets());
    };
    return DeferNotOk(SubmitIO(io_context_, std::move(deferred)));
  }

  Result<std::shared_ptr<ObjectInputFile>> OpenInputFile(const std::string& s,
                                                         S3FileSystem* fs) {