static void HeaderMapImplIterate(benchmark::State& state) {
  HeaderMapImpl headers;
  size_t num_callbacks = 0;
  addDummyHeaders(headers, state.range(0));
  auto counting_callback = [](const HeaderEntry&, void* context) -> HeaderMap::Iterate {
    (*static_cast<size_t*>(context))++;
    return HeaderMap::Iterate::Continue;
  };
  for (auto _ : state) {
    headers.iterate(counting_callback, &num_callbacks);
  }
  benchmark::DoNotOptimize(num_callbacks);
}
static void HeaderMapImplIterate(benchmark::State& state) {
  HeaderMapImpl headers;
  size_t num_callbacks = 0;
  addDummyHeaders(headers, state.range(0));
  auto counting_callback = [](const HeaderEntry&, void* context) -> HeaderMap::Iterate {
    (*static_cast<size_t*>(context))++;
    return HeaderMap::Iterate::Continue;
  };
  for (auto _ : state) {
    headers.iterate(counting_callback, &num_callbacks);
  }
  benchmark::DoNotOptimize(num_callbacks);
}