title: How to retrieve unspec'd headers with openapi-generator (spring)
body: <p>For our REST APIs, we have certain HTTP Request headers which will be set by infrastructure components, and should not be published to consumers in the OpenAPI spec.</p>
  
  <p>In the Spring Web based implementation code that we build (implementing the openapi-generator's generated interfaces), what is the right way to retrieve something like this from the HTTP Request? For example, a header which is not specified on the interface.</p>
  
  <p>I do not see any options in the openapi-generator itself to add the HttpServletRequest as a parameter to the generated methods. I am hoping there is a more generic way to get a handle to it in Spring / Spring Web.</p>