code: private void appendHeaders(OutputStream outputStream,
              InternetHeaders internetHeaders) {
          try {
              // Headers
              @SuppressWarnings("unchecked")
              Enumeration<Header> headers = internetHeaders.getAllHeaders();
              while (headers.hasMoreElements()) {
                  Header header = headers.nextElement();
                  String headerLine = String.format("%s: %s\r\n",
                          header.getName(), header.getValue());
                  outputStream.write(headerLine.getBytes("UTF-8"));
              }
  
              // Empty line
              outputStream.write("\r\n".getBytes("UTF-8"));
          } catch (UnsupportedEncodingException e) {
              throw new RuntimeException(e);
          } catch (IOException e) {
              throw new RuntimeException(e);
          }
      }
docs: Append headers.
  
  @param outputStream
  the output stream
  @param internetHeaders
  the internet headers