code: private WriteFuture writeHttpResponse(NextFilter nextFilter, IoSession session, HttpRequestMessage httpRequest, final HttpStatus httpStatus) {
          return writeHttpResponse(nextFilter, session, httpRequest, httpStatus, null);
      }
docs: Write a fresh HttpResponse from this filter down the filter chain, based on the provided request, with the specified http status code.
  
  @param nextFilter  the next filter in the chain
  @param session     the IO session
  @param httpRequest the request that the response corresponds to
  @param httpStatus  the desired status of the http response
  @return a writeFuture for the written response