HTTPSession::findTransaction(HTTPCodec::StreamID streamID) {
  auto it = transactions_.find(streamID);
  if (it == transactions_.end()) {
    return nullptr;
  } else {
    return &it->second;
  }
}
HTTPSession::findTransaction(HTTPCodec::StreamID streamID) {
  auto it = transactions_.find(streamID);
  if (it == transactions_.end()) {
    return nullptr;
  } else {
    return &it->second;
  }
}