function getRequestHeader(req, name) {
  // Pseudo API
  if (typeof req.getHeader === "function") {
    return req.getHeader(name);
  }

  return req.headers[name];
}
@template {IncomingMessage & ExpectedIncomingMessage} Request
@param {Request} req req
@param {string} name name
@returns {string | string[] | undefined} request header