code: @Override
     public void flushBufferedContent()
     {
        if (isResponseContentIntercepted())
        {
           try {
              bufferedResponseContent.close();
  
              ResponseContent buffer = new ResponseContentImpl(bufferedResponseContent.toByteArray(),
                       Charset.forName(getCharacterEncoding()));
              new ResponseContentInterceptorChainImpl(responseContentInterceptors).begin(new HttpBufferRewriteImpl(
                       request, this, servletContext), buffer);
  
              if (!Charset.forName(getCharacterEncoding()).equals(buffer.getCharset()))
                 setCharacterEncoding(buffer.getCharset().name());
  
              ServletOutputStream outputStream = isResponseStreamWrapped() ? wrappedOutputStream : super
                       .getOutputStream();
  
              if (outputStream != null)
                 Streams.copy(new ByteArrayInputStream(buffer.getContents()), outputStream);
  
              if (printWriter != null) {
                 printWriter.close();
              }
           }
           catch (IOException e) {
              throw new RewriteException("Error occurred when flushing response content buffered by "
                       + responseContentInterceptors, e);
           }
        }
     }
docs: Cause any buffered {@link ServletResponse} content to be processed and flushed to the client.