code: public static String format(Flags flags) {
          StringBuilder buf = new StringBuilder();
          buf.append('(');
          if (flags.contains(Flags.Flag.ANSWERED)) {
              buf.append("\\Answered ");
          }
          if (flags.contains(Flags.Flag.DELETED)) {
              buf.append("\\Deleted ");
          }
          if (flags.contains(Flags.Flag.DRAFT)) {
              buf.append("\\Draft ");
          }
          if (flags.contains(Flags.Flag.FLAGGED)) {
              buf.append("\\Flagged ");
          }
          if (flags.contains(Flags.Flag.RECENT)) {
              buf.append("\\Recent ");
          }
          if (flags.contains(Flags.Flag.SEEN)) {
              buf.append("\\Seen ");
          }
          String[] userFlags = flags.getUserFlags();
          if(null!=userFlags) {
              for(String uf: userFlags) {
                  buf.append(uf).append(' ');
              }
          }
          // Remove the trailing space, if necessary.
          if (buf.length() > 1) {
              buf.setLength(buf.length() - 1);
          }
          buf.append(')');
          return buf.toString();
      }
docs: Returns IMAP formatted String of MessageFlags for named user