Вы можете передать HttpResponse
в конструктор BasicResponseProducer
.
Так, например, в Http2FileServerExample в вопросе:
responseTrigger.submitResponse(new BasicResponseProducer(
HttpStatus.SC_OK, new FileEntityProducer(file, contentType)));
canстать:
BasicHttpResponse response = new BasicHttpResponse(HttpStatus.SC_OK);
response.setHeader("Access-Control-Allow-Origin", "*");
responseTrigger.submitResponse(new BasicResponseProducer(
response, new FileEntityProducer(file, contentType)));