code: protected void handleBinaryResponse(HttpServerExchange exchange, Response response) {
          exchange.dispatch(exchange.getDispatchExecutor(), Application.getInstance(BinaryHandler.class).withResponse(response));
      }
docs: Handles a binary response to the client by sending the binary content from the response
  to the undertow output stream
  
  @param exchange The Undertow HttpServerExchange
  @param response The response object
  
  @throws IOException