Function CreateRandomBuffer

cpp/src/arrow/util/bitmap_reader_benchmark.cc:45–50

// const int seed = std::rand();

static std::shared_ptr<Buffer> CreateRandomBuffer(int64_t nbytes) {
  auto buffer = *AllocateBuffer(nbytes);
  memset(buffer->mutable_data(), 0, nbytes);
  random_bytes(nbytes, /*seed=*/0, buffer->mutable_data());
  return buffer;
}

static void BitBlockCounterBench(benchmark::State& state) {
  int64_t nbytes = state.range(0);