Method AssertPayloadsEventually

cpp/src/arrow/util/io_util_test.cc:328–331

  }

  void AssertPayloadsEventually(const std::vector<uint64_t>& expected) {
    BusyWait(1.0, [&]() { return ReadPayloads().size() == expected.size(); });
    ASSERT_EQ(ReadPayloads(), expected);
  }

 protected:
  void ReadUntilEof() {