code: public void write(Writer writer)
          throws IOException
      {
          synchronized(writer)
          {
              for (int i=0;i<_fields.size();i++)
              {
                  Field field=(Field)_fields.get(i);
                  if (field!=null)
                      field.write(writer,_version);
              }
              writer.write(__CRLF);
          }
      }
docs: /* Write Extra HTTP headers.