code: public Writer writer(String contentType, Map<String, String> headers, int status){
          Result result = ResultBuilder.noBody(status).contentType(contentType);
          headers.entrySet().forEach(header -> result.addHeader(header.getKey(), header.getValue()));
          setControllerResult(result);
          //TODO TEST
          try {
              return context.responseWriter(result);
              //return context.responseWriter(); //TODO not possible, is it?
          } catch(Exception e) {
              throw new ControllerException(e);
          }
      }
docs: Produces a writer for sending raw data to HTTP clients.
  
  @param contentType content type. If null - will not be set on the response
  @param headers headers. If null - will not be set on the response
  @param status will be sent to browser.
  @return instance of a writer for writing content to HTTP client.